Browse Topic: Potassium

Items (36)
This standard describes general and detailed methods of sampling and testing for surface passivity of corrosion-resistant steel parts. These tests may also be useful to determine if there is a need for passivation.
AMS F Corrosion Heat Resistant Alloys Committee
MIO - A Cost Efficient and High Quality Raw Material for Brake Pads2014-01-24839/28/2014
Fierce competition demands more and more consideration for raw materials that are price competitive without the sacrifice of technical results. High and very often fluctuating raw material costs and availability challenge and complicate the calculation for brake pads raw materials. Therefore there is a strong demand for raw materials with high technical performance at stable predictable costs. For these reasons micaceous Iron Oxide (MIO) is evaluated. A case study describes the substitution of two well-established materials Zirconium Silicate and Potassium Titanate by micaceous iron oxide MIO in disk brake pads. MIO is a naturally occurring mineral with lamellar particle shape. The study compares the addition of 3 wt-% and 6 wt-% of Zirconium Silicate, Potassium Titanate and of MIO in a low-metallic formulation for disk brake pads. Regarding technical performance several properties are evaluated. Tests for friction coefficients are carried out according to the AK-Master SAE J2522. The results show, that MIO provides higher friction coefficients than the compared products Zirconium Silicate and Potassium Titanate. Whereas, Zirconium Silicate and Potassium Titanate induce typical rates in thermal expansion, MIO leads to shrinkage of the brake pad combined with a slightly increased thermal transmission. The noise behavior was tested on a dynamometer according to SAE J2521. The noise index of MIO is higher than of Potassium Titanate and lower than of Zirconium Silicate. With MIO disks wear is slightly lower and brake pad wear is equal in comparison to the substituted materials. Moreover MIO provides comparable processing behavior and comparable physical characteristics (bulk volume, green strength, pad shearing strength, compressibility). The case study shows that MIO substitutes Zirconium Silicate or Potassium Titanate with similar or better technical performance in the tested properties.
Mayer, VeronikaRichards, Brian
Sodium Contamination of Diesel Fuel, its Interaction with Fuel Additives and the Resultant Effects on Filter Plugging and Injector Fouling2013-01-268710/14/2013
Diesel fuel distilled from crude oil should contain no greater than trace amounts of sodium. However, fuel specifications do not include sodium; there is a limit of five parts per million for the amount of sodium plus potassium in fatty acid methyl esters (FAME) used as biodiesel. Sodium compounds are often used as the catalyst for the esterification process for producing FAME and sodium hydroxide is now commonly used in the refining process to produce ultra-low sulphur diesel (ULSD) fuel from crude oil. Good housekeeping should ensure that sodium is not present in the finished fuel. A finished fuel should not only be free of sodium but should also contain a diesel fuel additive package to ensures the fuel meets the quality standards introduced to provide reliable operation, along with the longevity of the fuel supply infrastructure and the diesel engines that ultimately burn this fuel. There has recently been an upsurge in reported field problems due to fouling of the fuel injection system in modern diesel engines. This can take the form of deposits in the fuel filters or within the fuel injectors themselves. Recent work proposed a mechanism whereby sodium contaminated fuel can undergo adverse reactions between the sodium compounds and fuel additives leading to the formation of material that can impede the operation of diesel fuel injectors. This paper presents new work carried out to enhance the understanding of this mechanism and demonstrates that the fate of any sodium contaminant is highly dependent on (i) the fuel additives present in the fuel (ii) the amount of water in the system, (iii) potentially the intensity of fuel/water mixing and (iv) the identity of the sodium salt involved in the reaction. This can lead to sodium accumulating in the water bottoms, forming sodium compounds that go on to plug fuel filters or which may cause injector fouling. The data found may explain the variation in engine test data regarding sodium induced fouling reported in the recent literature.
Barker, JimCook, StephenRichards, Paul
De-Icer Quantification and Phase Transition Detection by Raman Spectroscopy2013-01-21019/17/2013
Winter maintenance is based on the intervention of operating services, as well as the use of deicers. Each year, in France, thousands of tons of deicers are spread through runways and taxiways. On the airport sector, the main deicers are sodium or potassium acetates and formates. All these deicers aim to prevent ice formation (preventive strategy) and/or improve the ice melting of snow residual film (curative strategy) at temperatures below 0°C. The operating principle of these compounds is based on the lowering of the solution's freezing point once dissolved in water. The phase diagram's knowledge is predominant to determine the deicer's amount to be applied on the surface. It provides a way to optimize their amounts applied with respect to weather conditions, present or forecasted. The Center for Technical Studies of Equipment in East of France (CETE de l'Est) developed and implemented a method based on Raman spectroscopy to characterize aqueous solutions of airport de-icers. This application determines the phase transition temperatures of these solutions, according to their concentration. The spectroscopic tool being portable, its use could be easily conducted on the field, avoiding any sample collections. Furthermore, this spectroscopic tool enables the determination of the amount of de-icers used to generate the solution. This study also highlighted some differences between the freezing curves of different deicers, as well as the possible presence of phases with unknown chemical and mechanical properties, such as the metastable phase potassium formate. Additional lessons related to winter maintenance could be taken, on the shelf-life of these products as an example.
Durickovic, IvanaMarchetti, MarioPoissonnier, StephanieCasteran, GuillaumeMansour, RachelSchweigert, NathalieMars, Benoit
Colorimetric-Solid Phase Extraction (C-SPE): In-Flight Methodologies for the Facile Determination of Trace Level Indicators of Water Quality2008-01-22016/29/2008
At present, spacecraft water quality is assessed when samples collected on the International Space Station (ISS) are returned to Earth. Several months, however, may pass between sample collection and analysis, potentially compromising sample integrity by risking degradation. For example, iodine and silver, which are the respective biocides used in the U.S. and Russian spacecraft potable water systems, must be held at levels that prevent bacterial growth, while avoiding adverse effects on crew health. A comparable need exists for the detection of many heavy metals, toxic organic compounds, and microorganisms. Lead, cadmium, and nickel have been found, for instance, in the ISS potable water system at amounts that surpass existent requirements. There have been similar occurrences with hazardous organic compounds like formaldehyde and ethylene glycol. Microorganism counts above acceptable limits have also been reported in a few instances. The delays in analyzing potable water suspend implementation of any real-time correction scenarios to an on-board contaminant event. It is, therefore, critical that rapid, on-board methods be developed to monitor trace quantities of several indicators of quality in spacecraft drinking water supplies. To meet some of these needs, our laboratory has developed colorimetric-solid phase extraction (C-SPE). C-SPE is a sorption-spectrophotometric platform that entails the selective extraction and concentration of analytes by a membrane impregnated with a colorimetric reagent, followed by quantification on the membrane surface using a diffuse reflectance spectrophotometer. As such, we have designed and tested C-SPE methods for monitoring iodine, silver, nickel and lead. We have also devised methods to extend C-SPE to determinations of formaldehyde, pH, cadmium, and arsenic. This presentation provides a status report on the development of C-SPE to meet these needs, including results from tests in microgravity simulations via KC-135 and C-9 fights.
Porter, Marc D.Siperko, Lorraine M.Nordling, JohnHazen-Bosveld, April A.Shih, Chien-JuLipert, Robert J.Fritz, James S.
Potassium AMTEC Cell Performance1999-01-27028/2/1999
AMTEC systems have historically been operated with sodium as the working fluid, in large part because fabrication of beta”-alumina solid electrolyte (BASE) membranes has been substantially easier with sodium than with potassium or other alkali metals1. It has been anticipated that because potassium has a substantially higher vapor pressure for a given temperature, and because the best K-BASE conductivity falls only marginally below that for Na-BASE, potassium AMTEC cells could produce higher power at a given temperature or comparable power at a lower temperature than similar sodium cells. Operation at lower temperatures can reduce materials lifetime or compatibility problems, and for severely heat input constrained systems it could enhance efficiency by reducing parasitic thermal conduction losses. Recently K-BASE tubes have become available as a commercial product2 and conventional experiments to evaluate the performance of complete KAMTEC cells have become much more feasible. Previous experiments on K-BASE have focused primarily on measurements in non-power producing cell environments. One AMTEC cell experiment was carried out at low temperature.3 We report here initial experiments on the power output performance of KBASE with a conventional TiN cathode in a standardized single-pass AMTEC test cell. The performance data are compared to tests of Na-BASE cells under similar conditions and with similar electrodes. Peak power for a 6 cm2 TiN electrode on a K-BASE cell was substantially higher than has been observed for the best, comparable Na-BASE cells. The power improvement corresponded to that for a temperature increase of ~ 60 K for the Na- BASE cell.
Barkan, A.Hunt, T. K.Thomas, B.
Micronutrient Recovery from Inedible Plant Residues in Activated Sludge Cultures and Phanerochaete chrysosporium Inocula1999-01-20667/12/1999
Micronutrient recovery was investigated in two microbial systems, activated sludge and Phanerochaete chrysosporium (P. chrysosporium). Hydroponically grown crops, namely, tomato, peanut, wheat and a 50:50 mixture of peanut and wheat were used in the study. The experiments were conducted in shaker flasks on a 1% solids basis at 25°C for all crops and at 25°C, 40°C, 50°C and 60°C for tomato plant material. The micronutrient content of the leachate was determined initially and after 16, 32, 64, and 128 days of incubation. In order to determine the extent and rate of micronutrient release during the initial stages of incubation, when most of the solids degradation occurs, two separate experiments were conducted in batch reactors for 16 days. The micronutrient content of the batch reactor leachate was monitored on a daily basis. Micronutrients assessed included boron, manganese, iron, magnesium, zinc, copper, calcium, phosphorus and potassium. The effects of biological treatment, biological agents, and incubation time on micronutrient recovery were evaluated. The micronutrient content of the leachate, obtained from untreated inedible solid residues, is in general sufficiently high to support hydroponic plant growth. However, addition of certain micronutrients may be necessary depending on the type of crop leached. Recovery of micronutrients in the biologically treated samples exhibited substantial fluctuations both with incubation time and biological agent employed and was in general lower than micronutrient concentrations obtained from simple leaching.
Davies,, Kimberley A.Christodoulatos,, ChristosVaccari, David A.Korfiatis, George P.
SCHAEFFERS, JOSEPH
Items per page:
1 – 36 of 36