Physical properties of concrete with calcareous aggregate exposed to chloride solution at ambient temperature

2017 ◽  
Vol 1 (5) ◽  
pp. 26-30
Author(s):  
Dominika DĘBSKA
2007 ◽  
Vol 21 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Cláudio Maniglia-Ferreira ◽  
Eduardo Diogo Gurgel-Filho ◽  
João Batista Araújo Silva Jr ◽  
Regina Célia Monteiro de Paula ◽  
Judith Pessoa Andrade Feitosa ◽  
...  

This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also seeked to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130°. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130°C causes changes to its chemical structure which permanently alter its physical properties.


1920 ◽  
Vol 3 (1) ◽  
pp. 85-106 ◽  
Author(s):  
Jacques Loeb

1. This paper contains experiments on the influence of acids and alkalies on the osmotic pressure of solutions of crystalline egg albumin and of gelatin, and on the viscosity of solutions of gelatin. 2. It was found in all cases that there is no difference in the effects of HCl, HBr, HNO3, acetic, mono-, di-, and trichloracetic, succinic, tartaric, citric, and phosphoric acids upon these physical properties when the solutions of the protein with these different acids have the same pH and the same concentration of originally isoelectric protein. 3. It was possible to show that in all the protein-acid salts named the anion in combination with the protein is monovalent. 4. The strong dibasic acid H2SO4 forms protein-acid salts with a divalent anion SO4 and the solutions of protein sulfate have an osmotic pressure and a viscosity of only half or less than that of a protein chloride solution of the same pH and the same concentration of originally isoelectric protein. Oxalic acid behaves essentially like a weak dibasic acid though it seems that a small part of the acid combines with the protein in the form of divalent anions. 5. It was found that the osmotic pressure and viscosity of solutions of Li, Na, K, and NH4 salts of a protein are the same at the same pH and the same concentration of originally isoelectric protein. 6. Ca(OH)2 and Ba(OH)2 form salts with proteins in which the cation is divalent and the osmotic pressure and viscosity of solutions of these two metal proteinates are only one-half or less than half of that of Na proteinate of the same pH and the same concentration of originally isoelectric gelatin. 7. These results exclude the possibility of expressing the effect of different acids and alkalies on the osmotic pressure of solutions of gelatin and egg albumin and on the viscosity of solutions of gelatin in the form of ion series. The different results of former workers were probably chiefly due to the fact that the effects of acids and alkalies on these proteins were compared for the same quantity of acid and alkali instead of for the same pH.


2003 ◽  
Vol 50 (1) ◽  
pp. 7-12
Author(s):  
Toshiko Fukunaga ◽  
Ei Furukawa ◽  
Chie Yoneda ◽  
Etsuko Imai ◽  
Midori Kasai ◽  
...  

CrystEngComm ◽  
2018 ◽  
Vol 20 (3) ◽  
pp. 334-339
Author(s):  
Eleanor R. Townsend ◽  
Willem J. P. van Enckevort ◽  
Jan A. M. Meijer ◽  
Elias Vlieg

The creeping pattern observed when a saturated sodium chloride solution containing 1% (w/w) methylglycine diacetamide is allowed to dry at ambient temperature.


2017 ◽  
Vol 2 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Rasheed N. Abed ◽  
Nabeel K. Al-Sahib ◽  
Abdul Jabar N. Khalifa

The optical properties of TiO2/C in the district from (200-2000 nm) were examined by setting up the composites with wt. % concentration. The optical information evaluated and translated regarding the hypothesis of phonon-assisted direct electronic change; it is watched that the energy is influenced by doping sort of mineral composite utilized. The doping manufactured powders were examined through data analysis to validate the presence of these elements. This investigation for the influence of TiO2 was an addition on the microstructure of the carbon and electrical behavior of the composite was detected, this doped was gotten in a dry place at ambient temperature and its effect was studied from the physical properties of the energy gap. The optical measurement of the specimen was measured as a component of wavelength (λ), absorptivity that exhibit good results to absorb the solar energy for selective surfaces.


1942 ◽  
Vol 15 (3) ◽  
pp. 639-646
Author(s):  
T. S. Carswell ◽  
R. F. Hayes ◽  
H. K. Nason

Abstract The physical properties of plastics are markedly influenced by the ambient temperature, but comparatively few quantitative data on polystyrene have been published. The variation of flexural strength and deflection at break for compression-moulded polystyrene and for a number of other compression-moulded plastic materials at temperatures from —70° to +200° C was described by Nitsche and Salewski. Jenckel and Lagally determined the tensile strength of extruded polystyrene filaments at 30° to 60° C. The elongation at 20° to 90° C was reported for extruded and racked polystyrene foil by Müller. Since the mechanical properties of plastic materials are profoundly influenced by the methods used in preparing the test specimens, data on such properties are meaningless unless the details of preparation also are known. This paper describes variations in some of the mechanical properties of injection-moulded polystyrene over the range from —75° to +100° C. This method was chosen because injection moulding is by far the most commonly Used commercial process for the fabrication of polystyrene.


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