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Bad Materials Cause Failures
Published in Mohamed Abdallah El-Reedy, Assessment, Evaluation, and Repair of Concrete, Steel, and Offshore Structures, 2018
The chemical test is performed to measure some parameters and compare results with the product data sheet to determine if a sample matches with manufacturer specifications. For admixtures in the form of powder, the humidity will be removed from it by weight of about 3 g of the admixtures and remove the humidity and then determine of the percentage of the content of solid material.For liquid admixtures, It is required to put from 25 to 30 g of sand passing through sieve No. 30 into a glass bottle with rough surface opening with internal diameter 60 mm, height 30 mm and a cover of the provisions of closure.Put the bottle and the cover in the drying oven at 105°C–110°C and leave for 17 h ± 15 min.Cover the bottle and place it in the dryer until it reaches room temperature and then weigh it to the nearest 0.001 gm and note the weight (W).Place about 4 mL from the sample inside the bottle over the sand and weigh it to the nearest 0.001 and note the weight (W1).Put the bottle in the dryer oven at the same temperature for 17 h + 15 min.The bottle cover and place in the dryer at room temperature and weigh it to the nearest 0.001 g and note the weight (W2).
The Pocket Laboratory: The Blowpipe in Eighteenth-Century Swedish Chemistry
Published in Ambix, 2019
Carl Axel Arrhenius, an artillery officer who had studied at the Bureau’s chemical laboratory, identified an unusual black stone in the quarry at Ytterby in 1787, and two Bureau mineralogists published separate chemical analyses of it in 1788, including blowpipe results.74 The first chemical test described by the Swedish-Finnish chemistry professor Johan Gadolin in his 1794 essay on the stone in the Transactions of the Royal Swedish Academy of Sciences was a blowpipe test directly replicating those previous ones.75 Upon separation, Gadolin found 38 percent of it by weight to be an unknown earth. Though he stated his discomfort with claiming a new discovery, he has been consistently credited ever since with the discovery of both the earth yttria and, upon its isolation, the metal yttrium.76 Uppsala chemistry professor Anders Gustaf Ekeberg, in a follow-up study further examining yttria earth, reported in 1802 that he had isolated yet another unknown substance, this one a metal that he named tantalum.77
Population Balances for Extraction Column Simulations—An Overview
Published in Solvent Extraction and Ion Exchange, 2020
Hans-Jörg Bart, Hanin Jildeh, Menwer Attarakih
Equation (96) and Equation (97) are quite similar, each equation contains two fitting parameters (b4, b5); however, Equation (97) takes into account another important column geometry factor, the compartment volume (VT). Hence, the Schmidt[63] correlation might be more general to use especially for extraction column design. The model parameters in these equations were fitted to data obtained from single droplet experiments under certain conditions, e.g. chemical test system, column type (Kühni, RDC), mother droplet size, compartment geometry, rotational speed, etc. These single droplet data were collected and detailed specifications for the experimental conditions are summarized in Jildeh.[24]