Thermotechnical Calculation of Air Cavities by Rehabilitation of Wet Brickworks

2015 ◽  
Vol 1122 ◽  
pp. 214-218
Author(s):  
Jaroslav Solař
Keyword(s):  
Point Of View ◽  
Floor Level ◽  
Technical Evaluation ◽  
Internal Side ◽  
Air Cavities ◽  
Thermotechnical Calculation

For excessive wet masonry rehabilitation, except for other methods, the method of air cavities is used. These can be wall or floor cavities. The wall cavities may be situated either on the internal or the external side of the wall. From the height point of view, internal side cavities can be located under the floor or above the floor level. This contribution only deals with the cavities above the floor level. In the projection practice, the air cavities usually are designed only empirically. But it is necessary to carry out their thermal technical evaluation for their correct capacity. The matter of the evaluation is the topic of the following contribution.

Bloodhound Missile Evaluation

1962 ◽  
Vol 66 (621) ◽  
pp. 571-587 ◽  
Author(s):  
A. G. Biggs ◽  
A. R. Cawthorne
Keyword(s):  
Scientific Information ◽  
Point Of View ◽  
Operational Performance ◽  
Critical Examination ◽  
List Type ◽  
Complete Evaluation ◽  
Training Requirements ◽  
Detail Design ◽  
Technical Evaluation

The main objectives of Missile Evaluation Trials are a complete evaluation of the operational performance of the missile tested, a comprehensive assessment of the practical implications of regular operation of the weapon system from the user's point of view, and the feedback of scientific information to assist in future designs. This means that the trials must be planned to provide data on the following aspects: —(a) Scientific evaluation, i.e. determination of performance in the various conditions which will arise in operational use.(b) Technical evaluation, i.e. assessment of the detail design, workmanship, engineering and reliability and its influence on operational performance.(c) User evaluation, i.e. a practical critical examination of (and evolution of) handling and servicing procedures, personnel training requirements, installation requirements, logistics, and the numerous organisational steps necessary for the introduction of a new weapon into service.

Bull Run Fossil Plant: Technical Design Methods for Superheat Pendant Outlet Headers Replacement

2010 ◽  
Author(s):  
Salah E. Azzazy ◽  
Russell D. Cochran ◽  
Larry Sam Cox
Keyword(s):  
Power Plants ◽  
Point Of View ◽  
Piping System ◽  
Main Challenge ◽  
Tennessee Valley ◽  
Pipe Segment ◽  
Technical Evaluation ◽  
Engineering Mechanics ◽  
Main Steam ◽  
Unconventional Method

Bull Run Unit 1, rated at 950 MW, is the first of four fossil supercritical power plants at Tennessee Valley Authority (TVA). The unit went into commercial operation in 1967. The boiler (consists of two furnaces) built by Combustion Engineering (CE) has a radiant reheat twin divided furnace with tangential-fired coal burners. The unit’s maximum continuous rating (MCR) is 6,400,000 lbs/hr of main steam flow, with a design temperature of 1003°F and pressure of 3840 psig. Through the end of 2008, the unit had a total of approximately 670 cumulative starts and 333,185 operating hours. After years of numerous tube cracks at the Superheat Pendant Outlet Header/Tube Nozzles resulting in repetitive forced plant shutdowns, TVA decided to replace the two Outlet Headers (one for each furnace) in Fall 2008 during a reliability outage. Since the entire Main Steam piping system was installed with cold pull at almost every longitudinal pipe segment, the main challenge from the engineering mechanics point of view was how to restrain the piping system especially at the Crossover Outlet Links inside each furnace Penthouse. Further constructability reviews indicated that there were not enough adjacent steel frames inside each furnace to restrain the four Crossover Outlet Links in the three global directions during the Outlet Headers replacement inside each Penthouse. The only existing steel above the Crossover Outlet Links is embedded in asbestos insulation, and the removal of the insulation to provide access for the temporary restraints was determined to be costly and time consuming. The insulation removal would have also caused the scheduled outage to be extended significantly and unrealistically. After careful assessment, technical evaluation, and several constructability reviews; it was decided to take an unconventional approach for relieving the inherent cold pull in three global directions by cutting the four Mixing Headers outside each furnace. In addition, the concept of installing several temporary restraints was utilized for the vertical and lateral directions inside the furnace Penthouse, as well as several others outside the Boiler to control the piping configuration of the four Mixing Headers. This approach achieved two purposes: 1- relieving the inherent cold pulls in three global directions and 2- controlling the four Outlet Links pipe end positions with respect to the new Superheat Pendant Outlet Header nozzles. This unconventional method used to relieve the piping cold pull from outside the Boilers, to control the Outlet Links movements inside the Boiler Penthouses, and to restrain the entire Main Steam piping system was successfully developed and implemented in the Fall 2008 reliability outage to replace the two Superheat Pendant Outlet Headers. This unconventional method is described in this paper.

scholarly journals Technical Evaluation of MT Systems from the Developer's Point of View

1996 ◽  
Vol 3 (3) ◽  
pp. 83-102
Author(s):  
HITOSHI ISAHARA ◽  
HAJIME UCHINO ◽  
SHIHO OGINO ◽  
TOSHIYUKI OKUNISHI ◽  
SATOSHI KINOSHITA ◽  
...  
Keyword(s):  
Point Of View ◽  
Technical Evaluation

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

How a sheperd guides a sheep herd?

1984 ◽  
Vol 75 ◽  
pp. 331-337
Author(s):  
Richard Greenberg
Keyword(s):  
Point Of View ◽  
Single Ring ◽  
Damping Effects ◽  
Ring Particle

ABSTRACTThe mechanism by which a shepherd satellite exerts a confining torque on a ring is considered from the point of view of a single ring particle. It is still not clear how one might most meaningfully include damping effects and other collisional processes into this type of approach to the problem.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Radiation Damage in Ceramics

1982 ◽  
Vol 40 ◽  
pp. 600-603
Author(s):  
T. E. Mitchell ◽  
M. R. Pascucci ◽  
R. A. Youngman
Keyword(s):  
Radiation Damage ◽  
Outer Space ◽  
Point Of View ◽  
Nuclear Waste Storage ◽  
Waste Storage ◽  
Storage Media ◽  
Transmission Electron ◽  
Fundamental Point ◽  
Small Defect ◽  
Present Understanding

1. Introduction. Studies of radiation damage in ceramics are of interest not only from a fundamental point of view but also because it is important to understand the behavior of ceramics in various practical radiation enyironments- fission and fusion reactors, nuclear waste storage media, ion-implantation devices, outer space, etc. A great deal of work has been done on the spectroscopy of point defects and small defect clusters in ceramics, but relatively little has been performed on defect agglomeration using transmission electron microscopy (TEM) in the same kind of detail that has been so successful in metals. This article will assess our present understanding of radiation damage in ceramics with illustrations using results obtained from the authors' work.

Structural aspects of osmoregulation in porphyra

1978 ◽  
Vol 36 (2) ◽  
pp. 412-413
Author(s):  
C. Wiencke ◽  
A. Lauchli
Keyword(s):  
Culture Medium ◽  
Point Of View ◽  
Chemical Fixation ◽  
Cellular Organization ◽  
Osmotic Adaptation ◽  
Osmotic Balance ◽  
Activity Of Enzymes ◽  
Osmotic Agents ◽  
Vacuolar System ◽  
Structural Aspects

Osmoregulatory mechanisms in algae were investigated mainly from a physiological point of view (KAUSS 1977, HELLEBUST 1976). In Porphyra two osmotic agents, i. e. floridoside/isofloridoside (KAUSS 1968) and certain ions, such as K+ and Na+(EPPLEY et al. 1960) are considered for osmotic balance. Accumulations of ions (particularly Na+) in the cytoplasm during osmotic adaptation is improbable, because the activity of enzymes is generally inhibited by high ionic concentrations (FLOWERS et al. 1977).The cellular organization of Porphyra was studied with special emphasis on the development of the vacuolar system under different hyperosmotic conditions. Porphyra was cultivated at various strengths of the culture medium ASP 12 (PROVASOLI 1961) ranging from normal to 6 times concentrated (6x) culture medium. Por electron microscopy freeze fracturing was used (specimens fixed in 2% glutaraldehyde and incubated in 30% glycerol, preparation in a BALZERS BA 360 M apparatus), because chemical fixation gave poor results.

Elucidation of block boundaries as the dissolution channels in hydrated cement

1978 ◽  
Vol 36 (1) ◽  
pp. 484-485
Author(s):  
N.V. Belov ◽  
U.I. Papiashwili ◽  
B.E. Yudovich
Keyword(s):  
Liquid Phase ◽  
Grain Boundaries ◽  
Benzoyl Peroxide ◽  
Phase Contrast ◽  
Active Role ◽  
Point Of View ◽  
Hardened Cement ◽  
Hydrated Cement ◽  
Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

Electron microscopy in diagnostic virology

1984 ◽  
Vol 42 ◽  
pp. 70-73
Author(s):  
S. E. Miller
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Molecular Identification ◽  
Point Of View ◽  
Negative Stain ◽  
Viral Diagnosis ◽  
Electron Microscopist ◽  
Diagnostic Virology

The techniques for detecting viruses are many and varied including FAT, ELISA, SPIRA, RPHA, SRH, TIA, ID, IEOP, GC (1); CF, CIE (2); Tzanck (3); EM, IEM (4); and molecular identification (5). This paper will deal with viral diagnosis by electron microscopy and will be organized from the point of view of the electron microscopist who is asked to look for an unknown agent--a consideration of the specimen and possible agents rather than from a virologist's view of comparing all the different viruses. The first step is to ascertain the specimen source and select the method of preparation, e. g. negative stain or embedment, and whether the sample should be precleared by centrifugation, concentrated, or inoculated into tissue culture. Also, knowing the type of specimen and patient symptoms will lend suggestions of possible agents and eliminate some viruses, e. g. Rotavirus will not be seen in brain, nor Rabies in stool, but preconceived notions should not prejudice the observer into missing an unlikely pathogen.

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