Spectroscopy of chromium compounds in molten salts

1970 ◽  
Vol 48 (1) ◽  
pp. 55-58 ◽  
Author(s):  
H. C. Brookes ◽  
S. N. Flengas
Keyword(s):  
Absorption Spectrum ◽  
Ambient Temperature ◽  
Absorption Spectra ◽  
Molten Salts ◽  
Temperature Measurements ◽  
Dilute Solutions ◽  
Heats Of Solution ◽  
Chromium Compounds

Modifications to the Hitachi Perkin–Elmer 139 ultraviolet–visible spectrophotometer are described which enable absorption spectra of molten salts to be measured to 865 °C. The instrument can be readily reconverted for ambient temperature measurements. The solubilities and the limiting heats of solution of Ag2CrO4 and PbCrO4 in equimolar NaNO3–KNO3 have been measured spectrophotometrically from 250 to 350 °C. The absorption spectrum of dilute solutions of Cr(III) in CsCl has been measured, the octahedral CrCl63− being present in solution at 700 °C.

scholarly journals On the absorption spectra of dilute solutions

1895 ◽  
Vol 57 (340-346) ◽  
pp. 117-161 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Strong Solutions ◽  
Point Of View ◽  
Dilute Solutions ◽  
Copper Salts ◽  
Philosophical Magazine ◽  
Dispersive Power

The changes which occur in the colour of a solution when its concentration is changed, are closely connected with the simultaneous changes which occur in the molecular condition of the dissolved substance, and a study of these changes of colour may be expected therefore to furnish valuable information as to the molecular condition of the dissolved body. In a paper published in the ‘Philosophical Magazine’ for 1892, I described some experiments on the absorption spectra of solutions of copper salts, which were made from this point of view. It was found that with increasing dilution the spectra of the different salts examined tended to become the same. The solutions experimented with were, however, tolerably concentrated, which makes the interpretation of the results difficult, as, according to Kundt’s rule, the absorption spectrum of a substance varies to some extent with the dispersive power of the solvent in which it is dissolved, and, therefore, when working with strong solutions there is always the possibility that a change in the absorption, produced by changing the concentration of the solution, may be due to the alteration in dispersive power.

598 Temperature profiles of sunlight-exposed surfaces in a desert climate: Determining the risks for pavement burns.

2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S150-S151
Author(s):  
Paul J Chestovich ◽  
Richard Z Saroukhanoff ◽  
Syed F Saquib ◽  
Joseph T Carroll ◽  
Carmen E Flores ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Solar Irradiance ◽  
Time Of Day ◽  
Temperature Measurements ◽  
Solar Irradiation ◽  
Porous Rock ◽  
Solid Materials ◽  
Contour Plots ◽  
Desert Climate ◽  
Sunlight Intensity

Abstract Introduction In the desert climates of the United States, plentiful sunlight and high summer temperatures cause significant burn injuries from hot pavement and other surfaces. Although it is well known that surfaces reach temperatures sufficient to cause full-thickness burns, the peak temperature, time of day, and highest risk materials is not well described. This work measured continuous temperature measurements of six materials in a desert climate over a five-month period. Methods Six different solid materials common in an urban environment were utilized for measurement. Asphalt, brick, concrete, sand, porous rock, and galvanized metal were equipped with thermocouples attached to a data acquisition module. All solid materials except metal were placed in a 2’x2’x3.5” form, and identical samples were placed in both shade and direct sunlight. Ambient temperature was recorded, and sunlight intensity was measured using a pyranometer. Measurement time interval was set at three minutes. A computational fluid dynamics (CFD) model was created using Star CCM+ to validate the data. Contour plots of temperature, solar irradiance, and time of day were created using MiniTab for all surfaces tested. Results 75,000 temperature measurements were obtained from March through August 2020. Maximum recorded temperatures for sunlight-exposed samples of porous rock was 170 F, asphalt 166 F, brick 152 F, concrete 144 F, metal 144 F, and sand 143 F. Peak temperatures were recorded on August 6, 2020 at 2:10 pm, when ambient temperature was 120 F and sunlight intensity 940 W/m2 (Table). Temperatures ranged from 36 F - 56 F higher than identical materials in the shade at the same time. The highest daily temperatures were achieved between 2:00 pm to 4:00 pm due to maximum solar irradiance. Contour plots of surface temperature as function of solar irradiation and time of day were created for all surfaces tested. Nearly identical results obtained from the CFD models to the experimentally collected data, which validated the experimental data. Conclusions Surfaces exposed to direct, continuous sunlight in a desert climate achieve temperatures from 143 F to 170 F in the early afternoon and are high enough to cause significant injury with sufficient exposure. Porous rock reached the highest temperature, followed closely by asphalt. This information is useful to inform the public of the dangers of exposed surfaces in a desert climate.

X-Ray Absorption Fine Structure Study in FeTiO3

1997 ◽  
Vol 11 (16n17) ◽  
pp. 745-748 ◽  
Author(s):  
Rebekah Min-Fang Hsu ◽  
Kai-Jan Lin ◽  
Cheng Tien ◽  
Lin-Yan Jang
Keyword(s):  
Absorption Spectrum ◽  
Fine Structure ◽  
Absorption Spectra ◽  
Mixed Valence ◽  
Structure Study ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Absorption Fine ◽  
Trivalent State ◽  
X Ray Absorption

X-ray absorption fine structure XAFS spectroscopy has been used to determine the valence system for the Fe atom in ilmenite, FeTiO3 . This is the first XAFS data in FeTiO3 to our knowledge. The α- Fe2O3 data served as the standard in determining the ionization of the Fe atom in FeTiO3 . Observation of intensity and k-space are consistent. There was no evidence of mixed valence on comparing the FeTiO3 near edge X-ray absorption spectrum with α- Fe2O3 data. The absorption spectra suggest that iron is in the trivalent state in ilmenite.

scholarly journals Body Temperatures in Some Australian Mammals II.Peramelidae

1962 ◽  
Vol 15 (2) ◽  
pp. 386 ◽  
Author(s):  
PR Morrison
Keyword(s):  
Body Temperature ◽  
Ambient Temperature ◽  
Active Phase ◽  
Temperature Measurements ◽  
Temperature Cycle ◽  
Body Temperatures ◽  
Ambient Temperatures ◽  
Diurnal Temperature

Body temperature measurements on the short-nosed bandicoot (Thylacis obeaulus) have shown a nocturnal cycle with a range of 1� 2�C and a short active phase at 2200-0400 hr. The bilby or rabbit bandicoot (Macrotis lagoti8) had a sharply defined temperature cycle, with a range of almost 3�C after several months of captivity, during which the day-time resting temperature was progressively lowered from 36� 4 to 34� 2�C. Forced activity raised the diurnal temperature substantially but not to the nocturnal level. Forced activity did not raise the nocturnal level which was similar in the two species (37' O�C). Both species could regulate effectively at an ambient temperature of 5�C, but only Thylaci8 showed regulation at ambient temperatures of between 30 and 40�C.

Is there any Correlation between the Mobility and the Absorption Spectra of Solvated Electrons in Polar Solvents?

2000 ◽  
Vol 214 (10) ◽  
Author(s):  
P. Krebs
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Optical Absorption Spectrum ◽  
Chem Phys ◽  
Solvated Electrons ◽  
Polar Solvents ◽  
Excess Electrons

Some years ago Jay-Gerin and Ferradini attempted to establish a correlation between the optical absorption spectrum and the mobility of excess electrons in various polar solvents (J. Chem. Phys.

Friedel-Crafts reactions in ambient-temperature molten salts

1986 ◽  
Vol 51 (4) ◽  
pp. 480-483 ◽  
Author(s):  
Jeffrey A. Boon ◽  
Joseph A. Levisky ◽  
J. Lloyd Pflug ◽  
John S. Wilkes
Keyword(s):  
Ambient Temperature ◽  
Molten Salts
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