scholarly journals MODIFICATION OF LOW-REACTIVE ALUMINOSILICATES AS A METHOD FOR IMPROVEMENT OF ITS QUALITY WHEN GEOPOLYMER SYNTHESIS

2019 ◽  
Vol 4 (5) ◽  
pp. 131-139
Author(s):  
Н. Кожухова ◽  
Natal'ya Kozhuhova ◽  
Д. Данакин ◽  
Dmitriy Danakin ◽  
В. Строкова ◽  
...  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Water Resistance ◽  
Temperature Treatment ◽  
Average Density ◽  
High Temperature Treatment ◽  
Different Types ◽  
Dramatic Growth ◽  
Better Than ◽  
High Temperature Effect

Synthesis of binders and materials characterized by polycomponent composition, generally, is associated with necessity of improvement of certain properties or formation of principally new characteristics in this materials. In this paper hybrid geopolymers based on fly ash were synthesized using different types of mineral modifiers such as Portland cement (PC), kaolin, metakaolin (MK). It was defined, that values of compressive strength, water resistance and water absorption for PC-containing geopolymers are better than free of modifier geopolymer as well as for kaolin- and MK-containing geopolymers. It was determined that high-temperature treatment (at 600 °C) provides with reinforcing and improvement of water resistance of kaolin- and MK-containing hybrid geopolymers. PC-containing hybrid geopolymers demonstrated a sharp reducing in compressive strength and average density. For this system, in temperature range of 400–600 °C a dramatic growth of compressive strength is observed when average density grows or a constant. Thus, PC-containing hybrid geopolymers are not thermal resistant, that confirmed by degradation of its performance characteristics under high temperature effect.

The effect of high temperature on kernel dimensions and the type and occurrence of kernel damage in rice

1991 ◽  
Vol 42 (3) ◽  
pp. 485 ◽  
Author(s):  
T Tashiro ◽  
IF Wardlaw
Keyword(s):  
High Temperature ◽  
Oryza Sativa L ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Published Data ◽  
Starch Granules ◽  
Endosperm Tissue ◽  
Razor Blade ◽  
Light Refraction ◽  
Different Types

Rice (Oryza sativa L. cv. Calrose) growing at 27/22�C was either transferred to day/night temperatures ranging from 24/19 to 39/34�C 7days after heading and held at these temperatures until maturity, or transferred to a temperature of 36/31�C for 8 day periods at regular intervals commencing from heading. Kernel dimensions were measured directly and the types of kernel damage at maturity were characterized by direct viewing under the light microscope of intact and sectioned kernels, or by scanning electron microscopy of the exposed surface of kernels cut transversely with a razor blade. Kernel thickness was reduced most by high temperature treatments commencing 12 days after heading, but other kernel dimensions (length and width) were most sensitive to high temperature earlier in development. Sterility and pathenocarpy were most evident when temperature treatments commenced at heading (approximately 2 days before anthesis) and were greatest at the highest temperature (39/34�C). Abortive and opaque kernels were most evident when the high temperature commenced 4 days after heading and were also most numerous at the highest temperature tested. From observations on the morphology of the kernels it appears that temperatures above 27/22�C can interfere with the early stages of cell division and development in the endosperm. Chalky endosperm tissue occurred in several forms depending on both the temperature level and the timing of the temperature treatment. White-core kernels were only evident at a temperature of 27/22�C. White-back kernels were most numerous at 36/31�C and when the high temperature treatment commenced 16 days after heading. Milky-white kernels were found in all but the lowest temperature treatment (24/19�C), with a peak at 36/31�C and this type of damage was most evident when the high temperature treatment commenced 12 days after heading. Differences in endosperm cellular morphology were observed between the different types of damage, and in accord with other published data the chalky appearance was associated with the development of numerous air spaces between loosely packed starch granules and a change in light refraction.

scholarly journals Mechanical Properties of Cement Mortar after Dry–Wet Cycles and High Temperature

2020 ◽  
Vol 6 (5) ◽  
pp. 1031-1038
Author(s):  
Xiong Liang-Xiao ◽  
Song Xiao-Gang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Cement Mortar ◽  
Peak Stress ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Factors Affecting ◽  
Temperature Exposure ◽  
Compressive Tests

The dry–wet cycle and high temperature exposure are important factors affecting the normal use and durability of concrete structures. The objective of this work is to investigate the mechanical properties of cement mortar specimens after combinations of dry–wet cycles and high temperature exposures, uniaxial compressive tests on cement mortar specimens were carried out under the following two sets of conditions: (1) high temperature treatment followed by a dry–wet cycle and (2) a dry–wet cycle followed by high temperature treatment. The results show that the compressive strength of specimens increases with the number of dry–wet cycles. After a dry–wet cycle and then a high temperature treatment procedure, the compressive strength of a specimen will first decrease and then increase with the number of dry–wet cycles. The strain at the peak stress of cement mortar decreases as the number of dry–wet cycles increases. At present, there are few research results about the mechanical properties of concrete first after combinations of dry–wet cycles and high temperature exposures. The work in this paper can enrich the results in this area.

An experimental study on the fracture behaviors of marble specimens subjected to high temperature treatment

2020 ◽  
Vol 225 ◽  
pp. 106862 ◽  
Author(s):  
Qingzhen Guo ◽  
Haijian Su ◽  
Jiawei Liu ◽  
Qian Yin ◽  
Hongwen Jing ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Fracture Behaviors

scholarly journals Systemic Infection by Fusarium verticillioides in Maize Plants Grown Under Three Temperature Regimes

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1695-1700 ◽  
Author(s):  
A. Murillo-Williams ◽  
G. P. Munkvold
Keyword(s):  
High Temperature ◽  
Environmental Factors ◽  
Fusarium Verticillioides ◽  
Systemic Infection ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Kernel Infection ◽  
Temperature Regimes ◽  
Maize Plants ◽  
Systemic Development

Fusarium verticillioides causes seedling decay, stalk rot, ear rot, and mycotoxin contamination (primarily fumonisins) in maize. Systemic infection of maize plants by F. verticillioides can lead to kernel infection, but the frequency of this phenomenon has varied widely among experiments. Variation in the incidence of systemic infection has been attributed to environmental factors. In order to better understand the influence of environment, we investigated the effect of temperature on systemic development of F. verticillioides during vegetative and reproductive stages of plant development. Maize seeds were inoculated with a green fluorescent protein-expressing strain of F. verticillioides, and grown in growth chambers under three different temperature regimes. In the vegetative-stage and reproductive-stage experiments, plants were evaluated at tasseling (VT stage), and at physiological maturity (R6 stage), respectively. Independently of the temperature treatment, F. verticillioides was reisolated from nearly 100% of belowground plant tissues. Frequency of reisolation of the inoculated strain declined acropetally in aboveground internodes at all temperature regimes. At VT, the high-temperature treatment had the highest systemic development of F. verticillioides in aboveground tissues. At R6, incidence of systemic infection was greater at both the high- and low-temperature regimes than at the average-temperature regime. F. verticillioides was isolated from higher internodes in plants at R6, compared to stage VT. The seed-inoculated strain was recovered from kernels of mature plants, although incidence of kernel infection did not differ significantly among treatments. During the vegetative growth stages, temperature had a significant effect on systemic development of F. verticillioides in stalks. At R6, the fungus reached higher internodes in the high-temperature treatment, but temperature did not have an effect on the incidence of kernels (either symptomatic or asymptomatic) or ear peduncles infected with the inoculated strain. These results support the role of high temperatures in promoting systemic infection of maize by F. verticillioides, but plant-to-seed transmission may be limited by other environmental factors that interact with temperature during the reproductive stages.

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