Methods for testing the quality of lightweight cellular concrete during pouring

2022 ◽  
Vol 315 ◽  
pp. 125755
Author(s):  
Xin Liu ◽  
Xiaoxu Qian ◽  
Shikun Pu ◽  
Ke Sheng ◽  
Dongning Sun ◽  
...  
Keyword(s):  
Cellular Concrete

Problems of Autoclaved Aerated Concrete Treatment

2018 ◽  
Vol 284 ◽  
pp. 1069-1073
Author(s):  
A.A. Vishnevskiy ◽  
F.L. Kapustin
Keyword(s):  
Heat Transfer ◽  
Pressure Rise ◽  
Chemical Processes ◽  
Porous Space ◽  
Cold Air ◽  
Warm Up ◽  
Physical Chemical ◽  
Aerated Concrete ◽  
Cellular Concrete

The problems of autoclave c of cellular concrete are considered. It was shown that the key problem of autoclaving is the appearance of areas of concrete with different dark colors and a reduced strength. The main reason for their occurrence is the presence of air in the porous space of cellular concrete, which prevents heat transfer. Cold air does not allow the concrete to warm up to a temperature of 170-175 °C, which hinders the flow of physical-chemical processes of hardening. The proposed activities that improve the quality of autoclave processing and precluding the formation of «non-steamings» in the concrete: ensure the temperature inside cellular concrete mass of at least 80 °C before curing, the vacuum (P=‒0.5 Bar) before pressure rise in the autoclave, preventing the ingress of air into the autoclave at the beginning of the process.

scholarly journals Investigation of activated aluminum as a component of cellular concrete with complex porosation

2018 ◽  
Vol 251 ◽  
pp. 01013
Author(s):  
Viktoria Nelyubova ◽  
Artem Sumin
Keyword(s):  
High Stability ◽  
Cellular Concrete

In this paper indicators of the quality of activated aluminum, proposed for use as a poreforming agent in the production of cellular concrete with complex porisation are presented. The efficiency of ultrasonic homogenization of the poreforning agent in the presence of a mineral modifier of cellular concrete which provides high stability of the suspension in time is substantiated.

Statistical Analysis as an Instrument for Improving the Quality of Products from Cellular Concrete

2014 ◽  
Vol 670-671 ◽  
pp. 1624-1628 ◽  
Author(s):  
Elena Alekseevna Pospelova ◽  
Mikhail Yurievich Elistratkin ◽  
Daria Dmitrievna Netsvet
Keyword(s):  
Compressive Strength ◽  
Statistical Methods ◽  
Acceptance Testing ◽  
Minimum Level ◽  
Industrial Enterprises ◽  
Stable Conditions ◽  
Quality Of Products ◽  
The Stability ◽  
Cellular Concrete

Using statistical methods results of acceptance testing of products from autoclave cellular concrete of the enterprises of the Belgorod region were analyzed according to the measured compressive strength and density. It was found that when these indicators conform the regulations, their oscillations reach the frontiers of normal statistical distribution. It is shown that statistical methods can serve as a tool to control the quality of products and for finding problems in the production process with identifying the most important of them. The most expected causes of quality deterioration were identified. Recommendations for enterprise to bring the investigated process under the stable conditions were given. Thus it was shown that it is not always correct to judge the stability of manufacturing prosess only by output of quality products with a minimum level of defects. As an important tool for adjustment of production activities may be the use of statistical methods of quality management that can improve the efficiency of industrial enterprises.

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

Lithography below 100 nm

1983 ◽  
Vol 41 ◽  
pp. 96-99
Author(s):  
L. D. Jackel
Keyword(s):  
Spatial Distribution ◽  
Electron Beam ◽  
Electron Scattering ◽  
Electron Beam Lithography ◽  
Substrate Material ◽  
Local Electron ◽  
Electron Dose ◽  
Positive Resist ◽  
Exposure Process

Most production electron beam lithography systems can pattern minimum features a few tenths of a micron across. Linewidth in these systems is usually limited by the quality of the exposing beam and by electron scattering in the resist and substrate. By using a smaller spot along with exposure techniques that minimize scattering and its effects, laboratory e-beam lithography systems can now make features hundredths of a micron wide on standard substrate material. This talk will outline sane of these high- resolution e-beam lithography techniques.We first consider parameters of the exposure process that limit resolution in organic resists. For concreteness suppose that we have a “positive” resist in which exposing electrons break bonds in the resist molecules thus increasing the exposed resist's solubility in a developer. Ihe attainable resolution is obviously limited by the overall width of the exposing beam, but the spatial distribution of the beam intensity, the beam “profile” , also contributes to the resolution. Depending on the local electron dose, more or less resist bonds are broken resulting in slower or faster dissolution in the developer.

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

The Current Situation in Chemical Stabilization of Biological Materials

1972 ◽  
Vol 30 ◽  
pp. 132-133
Author(s):  
John H. Luft
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Molecular Level ◽  
Cross Linking ◽  
Chemical Stabilization ◽  
Specimen Preparation ◽  
Sufficient Condition ◽  
Radio Telescopes

With information processing devices such as radio telescopes, microscopes or hi-fi systems, the quality of the output often is limited by distortion or noise introduced at the input stage of the device. This analogy can be extended usefully to specimen preparation for the electron microscope; fixation, which initiates the processing sequence, is the single most important step and, unfortunately, is the least well understood. Although there is an abundance of fixation mixtures recommended in the light microscopy literature, osmium tetroxide and glutaraldehyde are favored for electron microscopy. These fixatives react vigorously with proteins at the molecular level. There is clear evidence for the cross-linking of proteins both by osmium tetroxide and glutaraldehyde and cross-linking may be a necessary if not sufficient condition to define fixatives as a class.

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