scholarly journals Effects of Temperature and Molecular Weight on the Porous Structure Formation of Polymer Chemical Gels

1999 ◽  
Vol 31 (5) ◽  
pp. 447-451 ◽  
Author(s):  
Toshiaki Miura ◽  
Ryoichi Kishi ◽  
Hisao Ichijo
Keyword(s):  
Molecular Weight ◽  
Porous Structure ◽  
Structure Formation ◽  
Effects Of Temperature

The effect of polyethylene glycol molecular weight on characteristics of the porous structure of silica materials

2013 ◽  
Vol 49 (2) ◽  
pp. 216-221 ◽  
Author(s):  
O. V. Yatskovskaya ◽  
O. N. Baklanova ◽  
T. I. Gulyaeva ◽  
V. A. Drozdov ◽  
V. A. Gorbunov
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Porous Structure ◽  
Silica Materials

Study of the Water-Glass Role in the Foam Glass Synthesis Using Glycerol Foaming Agent

2021 ◽  
Vol 316 ◽  
pp. 153-158
Author(s):  
Boris M. Goltsman ◽  
Lyubov A. Yatsenko ◽  
Natalia S. Goltsman
Keyword(s):  
Porous Structure ◽  
Structure Formation ◽  
Water Glass ◽  
Glass Batch ◽  
Foam Glass ◽  
Foaming Agent ◽  
Additive Type ◽  
Highly Porous ◽  
Material Porosity

The article discusses the peculiarities of the "water-glass – glycerol" foaming mixture components interaction during foam glass synthesis. The important role of the foaming additive type in the foam glass porous structure formation was described, the main foaming substances were listed. The obtaining and researching technology of the samples was described, the compositions of the initial batches using the "water-glass – glycerol" mixture were developed. It was shown that a material with a highly porous structure and density below 500 kg/m3 can be obtained only with the combined introduction of water-glass and glycerol. In this case, mixtures with a predominance of water-glass in the foaming mixture possess optimal properties. Using DSC, it was shown that the addition of water-glass to the mixture completely eliminates the evaporation of glycerol at lower temperatures and intensifies its combustion at higher temperatures. Thus, the addition of water-glass to the glycerol-based foam glass batch allows glycerol to be saved up to higher temperatures that increases the resulting material porosity.

scholarly journals Prebiotically-relevant low polyion multivalency can improve functionality of membraneless compartments

2020 ◽  
Author(s):  
Fatma Pir Cakmak ◽  
Saehyun Choi ◽  
McCauley O. Meyer ◽  
Philip C. Bevilacqua ◽  
Christine D. Keating
Keyword(s):  
Molecular Weight ◽  
Phase Separation ◽  
Structure Formation ◽  
Rna Structure ◽  
Salt Resistance ◽  
Origins Of Life ◽  
Complex Coacervation ◽  
The Impact ◽  
Local Ph

AbstractMultivalent polyions can undergo complex coacervation, producing membraneless compartments that accumulate ribozymes and enhance catalysis, and offering a mechanism for functional prebiotic compartmentalization in the origins of life. Here, we evaluated the impact of low, prebiotically-relevant polyion multivalency in coacervate performance as functional compartments. As model polyions, we used positively and negatively charged homopeptides with one to 100 residues, and adenosine mono-, di-, and triphosphate nucleotides. Polycation/polyanion pairs were tested for coacervation, and resulting membraneless compartments were analyzed for salt resistance, ability to provide a distinct internal microenvironment (apparent local pH, RNA partitioning), and effect on RNA structure formation. We find that coacervates formed by phase separation of the relatively shorter polyions more effectively generated distinct pH microenvironments, accumulated RNA, and preserved duplexes. Hence, reduced multivalency polyions are not only viable as functional compartments for prebiotic chemistries, but they can offer advantages over higher molecular weight analogues.

scholarly journals Modeling of Carbon Materials Porous Structure Formation

2018 ◽  
Author(s):  
R. Lisovskyi ◽  
I. Poplavskyi ◽  
B. Rachii ◽  
Z. Lyubun
Keyword(s):  
Porous Structure ◽  
Structure Formation ◽  
Carbon Materials

Interaction of Ultrafine Titanium Oxide Particles with Layered Vanadium Oxide Hydrate

1998 ◽  
Vol 520 ◽  
Author(s):  
S. Kittaka ◽  
K. Matsuno ◽  
S. Takahara
Keyword(s):  
Titanium Dioxide ◽  
Vanadium Oxide ◽  
Porous Structure ◽  
Structure Formation ◽  
Titanium Oxide ◽  
Vanadium Pentoxide ◽  
Layered Structure ◽  
Oxide Hydrate ◽  
Toxic Gases ◽  
Oxide Particles

ABSTRACTVanadium pentoxide hydrate was pillared with ultrafine titanium dioxide particles to form expanded layered structure (∼20 A) and thereby forming microporous substance (diameter =∼10 A). Porous structure formation and adsorption of some toxic gases (CO and NO) were discussed.

DNA replication and repair of Tilapia cells. II. Effects of temperature on DNA replication and ultraviolet repair in Tilapia ovary cells

1988 ◽  
Vol 89 (2) ◽  
pp. 263-272
Author(s):  
J.D. Chen ◽  
F.H. Yew
Keyword(s):  
Molecular Weight ◽  
Dna Replication ◽  
Dna Synthesis ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Control Level ◽  
High Molecular Weight Dna ◽  
Wide Range ◽  
Effects Of Temperature ◽  
Fish Cells

TO-2 is a fish cell line derived from the Tilapia ovary. It grows over a wide range of temperature (15–34 degrees C). While most fish cells lack DNA excision repair and are hypersensitive to ultraviolet light (u.v.), Tilapia cells are more u.v.-resistant than mammalian cells. In this paper we report the effects of temperature on DNA replication and u.v. repair in TO-2 cells. When the cells were moved from 31 degrees C to the sublethal high temperature of 37 degrees C, the rate of DNA synthesis first decreased to 60%, then speedy recovery soon set in, and after 8 h at 37 degrees C the rate of DNA synthesis overshot the 31 degrees C control level by 180%. When moved to low temperature (18 degrees C) Tilapia cells also showed an initial suppression of DNA synthesis before settling at 30% of the control level. u.v. reduced but could not block DNA synthesis completely. The inhibition was overcome in 3 h at 37, 31 and 25 degrees C, but not at 18 degrees C. Initiation of nascent DNA synthesis was blocked at 4 J m-2 in TO-2 cells compared with less than or equal to 1 J m-2 in mammalian cells. After 9 J m-2 u.v. irradiation, low molecular weight DNA replication intermediates started to accumulate, and they could be chased into high molecular weight DNA with little delay. TO-2 cells showed low levels of u.v.-induced excision repair; but this was prominent compared with other fish cells. The u.v.-induced incision rate has been measured at various temperatures, and the activation energy of incision estimated to be 13 kcal mol-1 (1 cal approximately equal to 4.184 J).

Processing Methods Used to Create High-Quality Porous Structure of Aerated Concrete

2020 ◽  
Vol 992 ◽  
pp. 212-217
Author(s):  
L.A. Suleymanova ◽  
A.S. Kolomatsky ◽  
M.V. Marushko
Keyword(s):  
Porous Structure ◽  
Structure Formation ◽  
Volume Ratio ◽  
Effect Of Temperature ◽  
Thermal Vacuum ◽  
High Quality ◽  
Molding Sand ◽  
Processing Methods ◽  
Concrete Production ◽  
Aerated Concrete

The efficiency of porous structure formation in aerated concrete can be improved by including the methods of thermal vacuum compaction or thermal vacuum compaction with vibration into the process as a means of creating high-quality composite cellular concrete. A graphic model of a phase composition change in the aerated concrete mix was developed allowing for an evaluation of the recipe and the mode of bubble porosity generation during hardening. This provides a control over the manufacturing processes and helps to produce aerated concrete with the specified porosity balance, which defines product properties.The effect of temperature and vacuum on molding sand during the initial stage of manufacture is proportional to the bubble porosity volume, which is important for a high-quality porous structure formation. In addition to the above, account must be taken of the combined effect of temperature, vacuum and volume ratio of phases in the base mix when using the proposed methods.Introduction of the developed processing methods into the manufacturing process improves the technology of aerated concrete production and allows for a fabrication of the finest advanced heat insulating and structural and heat insulating products.

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