New Silicone-Resin-Compounds for Casting and Molding Applications

2019 ◽  
Vol 809 ◽  
pp. 15-22
Author(s):  
Jens Lambrecht ◽  
Markus Winterer
Keyword(s):  
Heat Stress ◽  
Chemical Composition ◽  
Electrical Machines ◽  
Silicone Resin ◽  
Good Property ◽  
Low Viscosity ◽  
Property Profile ◽  
General Experience ◽  
The Moment ◽  
Resistance To Heat

Silicone resins are manufactured and supply in various delivery forms since decades. The impregnation of large electrical machines demonstrates a main application in the field of electrical insulation technology at the moment. Silicone resins are characterized by outstanding resistance to heat stress at high temperatures in general. Experience has shown that they are also very stable against exposure to UV radiation. Based on the expected very good property profile, Wacker Chemie AG developed a solvent-free, low-viscosity silicone resin for use as a binder for castable and moldable products. The article presents the chemical composition of silicone resins, the resulting properties of the resin and selected results of the extensive work for the evaluation of possible fillers and filler mixtures as well as first experience with the processing.

scholarly journals Kaolinite Claystone-Based Geopolymer Materials: Effect of Chemical Composition and Curing Conditions

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 444 ◽  
Author(s):  
Pavlína Hájková
Keyword(s):  
Chemical Composition ◽  
Water Glass ◽  
Chemical Elements ◽  
Solidification Process ◽  
Ease Of Use ◽  
Raw Material ◽  
Curing Conditions ◽  
Low Viscosity ◽  
Lower Porosity ◽  
Curing Methods

This work describes the role of chemical composition and curing conditions in geopolymer strength, leachability of chemical elements and porosity. The study focuses on geopolymer material prepared from calcined kaolinite claystone, which is not studied frequently as a raw material for geopolymer production, although it has a high application potential as it is easily commercially available and allows preparation of geopolymers with low viscosity. The composition of geopolymers and their curing methods were selected considering their ease of use in the praxis. Therefore, the potassium water glass itself was used as alkali activator without any KOH or NaOH addition. Chemical composition was changed only by the density of water glass in the range of 1.2 to 1.6 g·cm−3. Geopolymers were cured at a temperature within the range of 5 °C–70 °C to speed up the solidification process as well as by microwave radiation. High compressive strengths were obtained for geopolymers with the highest densities of the water glass (1.5 and 1.6 g·cm−3) in dependence on various curing conditions. Higher strengths were achieved in the case of samples where the solidification was not accelerated. The samples cured at lower temperatures (5 °C) showed lower porosity compared to the other curing types. The lowest leachability of Si and alkalis was reached for the samples with water glass density 1.5 g·cm−3.

scholarly journals Chemical composition and functional properties of malted corn flours

1998 ◽  
Vol 41 (2) ◽  
Author(s):  
Maria Victória E. Grossmann ◽  
José Marcos G. Mandarino ◽  
Márcia Cristina Yabu
Keyword(s):  
Response Surface Methodology ◽  
Chemical Composition ◽  
Functional Properties ◽  
Water Solubility ◽  
Absorption Index ◽  
Corn Flour ◽  
Low Viscosity ◽  
Gibberelic Acid ◽  
Paste Viscosity ◽  
Physicochemical And Functional Properties

Flours with different physicochemical and functional properties were obtained from malted corn. Response surface methodology (RSM) was used to study the effects of malting time (1,3, 5 days), malting temperature (20, 25, 30º C) and gibberelic acid concentration (0.0; 0.5; 1.0 %) on these properties. The chemical composition and paste viscosity of flours were significantly affected by malting time and temperature, while water solubility index (WSI) and water absorption index (WAI) varied only with malting time. Gibberelic acid did not significantly influenced any of the studied properties. Germination at 20-25ºC for 3 days was recomended to obtain corn flour with high WAI, low viscosity and medium WSI, without excessive loss of proteins.

scholarly journals Splenic Gene Expression Signatures in Slow-Growing Chickens Stimulated in Ovo with Galactooligosaccharides and Challenged with Heat

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 474 ◽  
Author(s):  
Elzbieta Pietrzak ◽  
Aleksandra Dunislawska ◽  
Maria Siwek ◽  
Marco Zampiga ◽  
Federico Sirri ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heat Stress ◽  
Broiler Chickens ◽  
Physiological Saline ◽  
Negative Effects ◽  
In Ovo ◽  
Stress Related Genes ◽  
The Impact ◽  
Slow Growing ◽  
Resistance To Heat

Galactooligosaccharides (GOS) that are delivered in ovo improve intestinal microbiota composition and mitigate the negative effects of heat stress in broiler chickens. Hubbard hybrids are slow-growing chickens with a high resistance to heat. In this paper, we determined the impact of GOS delivered in ovo on slow-growing chickens that are challenged with heat. The experiment was a 2 × 2 × 2 factorial design. On day 12 of incubation, GOS (3.5 mg/egg) was delivered into the egg (n = 300). Controls (C) were mock-injected with physiological saline (n = 300). After hatching, the GOS and C groups were split into thermal groups: thermoneutral (TN) and heat stress (HS). HS (30 °C) lasted for 14 days (days 36–50 post-hatching). The spleen (n = 8) was sampled after acute (8.5 h) and chronic (14 days) HS. The gene expression of immune-related (IL-2, IL-4, IL-6, IL-10, IL-12p40, and IL-17) and stress-related genes (HSP25, HSP90AA1, BAG3, CAT, and SOD) was detected with RT-qPCR. Chronic HS up-regulated the expression of the genes: IL-10, IL-12p40, SOD (p < 0.05), and CAT (p < 0.01). GOS delivered in ovo down-regulated IL-4 (acute p < 0.001; chronic p < 0.01), IL-12p40, CAT and SOD (chronic p < 0.05). The obtained results suggest that slow-growing hybrids are resistant to acute heat and tolerant to chronic heat, which can be supported with in ovo GOS administration.

THE EFFECT OF EXTENDED EXPOSURE TO A HOT ENVIRONMENT ON THE RESPONSE OF THE CHICKEN TO HYPERTHERMIA

1963 ◽  
Vol 41 (3) ◽  
pp. 805-815 ◽  
Author(s):  
Harold S. Weiss ◽  
Harry Frankel ◽  
Keith G. Hollands
Keyword(s):  
Heat Stress ◽  
Minute Volume ◽  
Covariance Analysis ◽  
Regression Coefficients ◽  
Volume Formula ◽  
Hot Environment ◽  
Cardiovascular Variables ◽  
Extended Exposure ◽  
Resistance To Heat ◽  
Better Than

Adult female White Leghorns lived for 12 weeks at either 32–35 °C and 50–60% R.H. (adapted) or 22–24 °C, R.H. uncontrolled (controls). Hyperthermia was induced by exposing the restricted animal to 40.5 °C and 60% R.H. Body temperature (TB), respiratory rate (RR), minute volume [Formula: see text], tidal volume (VT), heart rate (HR), and systolic, diastolic, and pulse pressure (SBP, DBP, and PP) were monitored at [Formula: see text] changes in TB. Adapted birds resisted hyperthermia better than controls, but the time–TB relationship was biphasic. Between TB of 42.0 and 43.5 °C regression coefficients relating time to TB were not different (adapted, 20.4 ± 0.6 and controls, 22.1 ± 0.8 minute/°C) but they did diverge significantly between TB of 44.0 and 45.5 °C (35.9 ± 0.8 and 25.6 ± 0.8 minute/°C). Body weight (BW), RR, [Formula: see text], HR, SBP, and DBP were significantly lower in adapted birds before hyperthermia. Covariance analysis indicated that, of these differences, the lower BW handicapped and the lower [Formula: see text], SBP, and DBP aided the adapted birds in resisting heat stress. The pattern of change in respiratory–cardiovascular variables during hyperthermia was similar for both groups. Covariance analysis of such quantitative differences as did exist indicated that higher values for RR and V either had no effect on or handicapped the adapted birds in their resistance to heat stress. The results suggest that adaptation depends on mechanisms other than increased respiratory elimination of heat.

The Inertial Effect in Rotational Fluorescence Depolarization

1992 ◽  
Vol 47 (9) ◽  
pp. 971-973 ◽  
Author(s):  
A. Kawski ◽  
P. Bojarski ◽  
A. Kubicki
Keyword(s):  
Empirical Equation ◽  
Molecular Geometry ◽  
Moment Of Inertia ◽  
Experimental Results ◽  
Inertial Effect ◽  
Fluorescence Depolarization ◽  
Moments Of Inertia ◽  
Low Viscosity ◽  
The Moment ◽  
Semi Empirical

Abstract The influence of the moment of inertia on the rotational fluorescence depolarization is discussed. Based on experimental results obtained for five luminescent compounds: 2,5-diphenyloxazole (PPO), 2,2'-p-phenylene-bis(5-phenyloxazole) (POPOP), p-bis[2-(5-α-naphthyloxazolyl)]-benzene (α-NOPON), 4-dimethylamino-ω-methylsulphonyl-trans-styrene (3a) in n-parafines at low viscosity (from 0.22 x 10-3 Pa • s to 0.993 x 10-3 Pa • s) and diphenylenestilbene (DPS) in different solvents, a semi-empirical equation is proposed, yielding moments of inertia that are only two to five times higher than those estimated from the molecular geometry

scholarly journals Interactions with a Complex Microbiota Mediate a Trade-Off between the Host Development Rate and Heat Stress Resistance

2020 ◽  
Vol 8 (11) ◽  
pp. 1781
Author(s):  
Samuel Slowinski ◽  
Isabella Ramirez ◽  
Vivek Narayan ◽  
Medha Somayaji ◽  
Maya Para ◽  
...  
Keyword(s):  
Life History ◽  
Heat Stress ◽  
Stress Resistance ◽  
Life History Traits ◽  
Soil Microbes ◽  
Development Rate ◽  
Heat Stress Resistance ◽  
Host Life ◽  
Host Development ◽  
Resistance To Heat

Animals and plants host diverse communities of microorganisms, and these microbiotas have been shown to influence host life history traits. Much has been said about the benefits that host-associated microbiotas bestow on the host. However, life history traits often demonstrate tradeoffs among one another. Raising Caenorhabditis elegans nematodes in compost microcosms emulating their natural environment, we examined how complex microbiotas affect host life history traits. We show that soil microbes usually increase the host development rate but decrease host resistance to heat stress, suggesting that interactions with complex microbiotas may mediate a tradeoff between host development and stress resistance. What element in these interactions is responsible for these effects is yet unknown, but experiments with live versus dead bacteria suggest that such effects may depend on bacterially provided signals.

Features of Amorphization of the Fe-TM-Nd-REM-B Alloys System at Melt Quenching by Gas Atomization

2019 ◽  
Vol 31 ◽  
pp. 51-55
Author(s):  
Mikhail Sorokovikov ◽  
Valeriy V. Savin ◽  
Ludmila A. Savina ◽  
V.A. Chaika ◽  
I.S. Zherebcov
Keyword(s):  
Chemical Composition ◽  
Cooling Rate ◽  
Primary Crystallization ◽  
Primary Phase ◽  
Gas Atomization ◽  
Spherical Powder ◽  
Similar Chemical ◽  
Powder Particles ◽  
The Moment ◽  
Triple Eutectic

Gas atomization powders (GAP) chemical composition which corresponds to the first area of the phase equilibrium, and the fraction that ensures a cooling rate of a separate powder particle of more than 103K/s contains an amorphous component of two types: the first (AC1) has a chemical composition similar to that of the alloy; and the second (AC2) has a chemical composition of the triple eutectic. AC1 is mostly localized on the surface of the powder particles (in the form of layers, shells, nodules) or are detected in the whole volume of the spherical powder particles with its size less than 5 μm. The authors hold that during gas atomization, powder particles of this size have a cooling rate ≥ 105 K/s. Alloys having a similar chemical composition at similar cooling rates are also amorphized by quenching from the liquid state. This proves that an amorphous alloy of the first type is formed directly from a supercooled melt. While AC2 (enriched by Nd) is formed on the border or in the between the crystal phase Fe14Nd2B of the remaining (after primary crystallization during the primary phase) melt enriched by the moment of the solidification of Nd.

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