scholarly journals Change of Calibration Parameters in Frequently Used Vials in Benzene Scintillation Counting

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 737-742 ◽  
Author(s):  
Herbert Haas
Keyword(s):  
Strong Acid ◽  
Scintillation Counting ◽  
Calibration Data ◽  
Acid Solutions ◽  
Calibration Parameters ◽  
Made In

Scintillation counting vials used for counting synthesized benzene accumulate an inside coating which is insoluble in benzene. This coating reduces the photon transfer from the vial and lowers its observed background. Age calculations that include calibration data collected with other vials may be inaccurate if this effect is not considered. Frequent cleaning of the counting vials with strong acid solutions keeps the coating from accumulating.A sample counting vial cleaned only with photospectrometric grade benzene between 67 different sample benzene fillings made in a 20-month period showed, during counting, an efficiency lowered by 2.8% and a background lowered by 8.7%. Age calculations for a 10 ka old sample made with calibration data from “matched” vials would yield a result too old by 515 yr.

Corrosion behavior of ZrB 2 –SiC–Graphite ceramic in strong alkali and strong acid solutions

2016 ◽  
Vol 42 (2) ◽  
pp. 2926-2932 ◽  
Author(s):  
Zhi Wang ◽  
Quanyue Zhao ◽  
Li Jing ◽  
Zhanjun Wu ◽  
Ximiao Sun
Keyword(s):  
Corrosion Behavior ◽  
Strong Acid ◽  
Acid Solutions

THE SEPARATION OF SMALL AMOUNTS OF THE PLATINUM METALS: 1. THE COLORIMETRIC DETERMINATION OF RHODIUM AND ITS SEPARATION FROM IRIDIUM

1961 ◽  
Vol 39 (12) ◽  
pp. 2389-2393 ◽  
Author(s):  
D. E. Ryan
Keyword(s):  
Hydrochloric Acid ◽  
Stannous Chloride ◽  
Colorimetric Determination ◽  
Acid Solutions ◽  
Platinum Metals ◽  
Hydrochloric Acid Solutions ◽  
Product Separation ◽  
Chromous Chloride ◽  
Made In

A method for separating small amounts of rhodium from iridium is described. In 3 to 9 M hydrochloric acid solutions, the amber-to-red complex of bivalent rhodium with 4,5-dimethyl-2-mercaptothiazole is formed after reduction of tervalent rhodium with chromous or stannous chloride. Rhodium is quantitatively separated from iridium by chloroform extraction of this product; separation can be made in solutions that have been fumed with sulphuric acid if chromous chloride is used for the prior reduction of the rhodium. The complex, after removal of the chloroform, is dissolved in dilute hydrochloric acid, and the optical density of the resulting colored solution is measured.

Etude cinétique des systèmes Cu(II)•Adénosine et Cu(II)•D-Ribose

1972 ◽  
Vol 50 (19) ◽  
pp. 3117-3123 ◽  
Author(s):  
G. Boivin ◽  
M. Zador
Keyword(s):  
Kinetic Parameters ◽  
Acidic Medium ◽  
Temperature Jump ◽  
Strong Acid ◽  
Basic Medium ◽  
Stopped Flow ◽  
Acid Solutions ◽  
Flow Method ◽  
Kinetics Of ◽  
Adenine Base

The kinetics of the formation and dissociation of Cu(II) complexes of adenosine have been determined in acidic and basic medium. In acidic medium, the complex is formed between the Cu(II) and the adenine base and the kinetic parameters have been obtained in this case using a temperature jump method. In basic medium, only the dissociation of the complexes could be studied by a stopped-flow method, by addition of EDTA or strong acid solutions. In these complexes, Cu(II) is bridged with ribose hydroxyls. Finally, D-ribose has also been studied for comparison in the same conditions. The mechanism of these reactions is discussed.

The Mechanical Properties of PSA Fibers after Corrosion

2010 ◽  
Vol 146-147 ◽  
pp. 221-224
Author(s):  
Xin Yan Yuan ◽  
Heng Gen Shen ◽  
Zhen Hua Wang ◽  
Wei Li Hou
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Breaking Strength ◽  
Retention Rate ◽  
Acid Corrosion ◽  
Strong Acid ◽  
Elongation Rate ◽  
Scanning Electron ◽  
Better Than ◽  
Made In

In order to reveal the influence of acidic gas SO2 and CaO etc alkali substances which are contained in industrial furnaces smoke to the strength of PSA fiber, tests are made in different acid and alkali conditions, and the changes of its surface morphology were observed by scanning electron microscope (SEM). The results show that: PSA has better acid corrosion resistance than alkali corrosion resistance. Its acid corrosion resistance is similar to the domestic aramid. PSA is better than Nomex in the concentration of 5% H2SO4. Its alkali corrosion resistance is worse than domestic aramid. The retention rate of breaking strength drop to 60.80% and 69.52% respectively after treated in the concentration of 5% H2SO4 for 48 hours and in the concentration of 5% NaOH for 4 hours. The elongation rate decline to 68.14% and 40.22% respectively, and the elongation rate fell to 68.14% and 40.22% respectively. Therefore, the PSA must be dealt against corrosion when used in strong acid or alkali environment.

scholarly journals The utilization demineralized rice husk waste for biofuel source via pyrolysis: thermogravimetric analysis and kinetic study

2019 ◽  
Vol 280 ◽  
pp. 05019
Author(s):  
Hesti Wijayanti ◽  
Iryanti Fatyasari Nata ◽  
Rinny Jelita
Keyword(s):  
Nitric Acid ◽  
Thermogravimetric Analysis ◽  
Acid Solution ◽  
Rice Husk ◽  
Nitric Acid Solution ◽  
Agricultural Waste ◽  
Solution Treatment ◽  
Strong Acid ◽  
Raw Material ◽  
Acid Solutions

Rice husk is considered as agricultural waste that causes environmental problem during its handling. In this study, rice husk was treated with acid (citric acid and nitric acid) solutions prior used as raw material for producing biofuel and chemicals via pyrolysis. The pyrolysis behaviors of rice husk treated with water and acid solutions have been investigated through thermogravimetric analysis from room temperature to 600 oC at the heating rate of 10oC/min under 50 ml/min nitrogen flow. Demineralization treatment using strong acid (nitric acid) solution showed more impacts to the rice husk in thermogravimetric analysis, i.e. lower ash content, less minerals content and thermal stability increased. One step model kinetic resulted the lowest activation energy (12.8709 kJ/mol) occured at the 5% nitric acid solution treatment. Excellent agreement between the experimental data and model predictions was found with 8.63% of the relative error. In other words, demineralization using 5% nitric acid solution would improve rice husk performance during its pyrolysis reaction for producing biofuel.

Diurnal pH changes in duodenum of conscious dogs

1980 ◽  
Vol 238 (2) ◽  
pp. G91-G96 ◽  
Author(s):  
Z. Itoh ◽  
R. Honda ◽  
I. Aizawa
Keyword(s):  
Strong Acid ◽  
Force Transducer ◽  
Weak Acid ◽  
Conscious Dogs ◽  
Ph Change ◽  
Motor Patterns ◽  
Ph Changes ◽  
Duodenal Ph ◽  
Measured Volume ◽  
Made In

Continuous measurements of intraduodenal pH changes were made in five healthy conscious dogs by means of a miniature pH electrode inserted into the duodenum through a chronically implanted duodenal cannula. Gastric motor activity was also recorded simultaneously by means of a chronically implanted force transducer. When dogs were fed once a day with a measured volume of dog food, it was found that 24-h pH changes in the duodenal contents could be divided into three major periods: the weak acid period, the strong acid period, and alkaline period. The weak acid period lasted for 9.2 +/- 0.43 h after feeding with the duodenal pH ranging from 7.0 to 4.0. The weak acid period was gradually changed to the strong acid period in which the duodenal pH fluctuated widely from 8.0 to 1.0. This period lasted for 5.2 +/- 0.26 h. After the strong acid period, pH of the duodenum abruptly turned alkaline and remained between 7.0 and 8.3 until the next meal. These three periods of pH change are closely related to those of three different gastric motor patterns; the digestive, intermediate, and interdigestive patterns, respectively.

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