Browse Topic: Calcium
A unique wristwatch contains multiple modules, including a sensor array, a microfluidic chip, signal processing, and a data display system to monitor chemicals in human sweat. It can continuously and accurately monitor the levels of potassium (K+), sodium (Na+), and calcium (Ca2+) ions
Researchers have developed a biomimetic scaffold that generates electrical signals upon the application of pressure by utilizing the unique osteogenic ability of hydroxyapatite (HAp). HAp is a basic calcium phosphate material found in bones and teeth
In Penn’s Clean Energy Conversions Lab, researcher Peter Psarras and colleagues are repurposing waste from industrial mines, storing carbon pulled from the atmosphere into newly formed rock. The team sees great environmental potential in mine tailings, the sand and sludge left behind after the sought-after ore gets removed. With samples in the lab, they’re trying to determine just how much calcium and magnesium each contains, how to best carbonate it with CO2, how and where they can store the result, and whether the process is scalable
A research group has developed a prototype calcium (Ca) metal rechargeable battery capable of 500 cycles of repeated charge-discharge – the benchmark for practical use
Researchers have reported a sustainable, insoluble, and chiral photonic cellulose nanocrystal patch for calcium ion (Ca2+) sensing in sweat
Researchers have pioneered a 3D printable ink that contains Sporosarcina pasteurii: a bacterium that, when exposed to a urea-containing solution, triggers a mineralization process that produces calcium carbonate (CaCO3). The ink — dubbed BactoInk — can be used to 3D print virtually any shape, which will then gradually mineralize over the course of a few days
This specification establishes testing methods for testing chemical composition in nickel- and cobalt-based alloys
Biodiesel was found to be a promising alternative source to diesel fuel for which the engine characteristics can be improved by means of Nano additives. The present work deals with the effect of calcium oxide Nano fluid on the performance, emission and combustion characteristics of diesel engine fuelled with ternary blends comprising of Calophyllum, Neem biodiesel and diesel fuel. Calcium oxide was synthesized by means of calcination process from Mactra Corallina sea shell which imparts novelty to the present work. The calcium oxide was converted into Nano particles by means of ball milling and dispersed in distilled water using ultra-sonication to form Nano fluids. The stability of Nano fluid was found to be effective at 100 ppm. Blend selected for the study has the proportion of 95 % biodiesel (B20), 3 % Nano fluid and 2 % Tween 20 surfactant labelled as B20 + NF. Results show that addition of Nano fluid to biodiesel increased Brake Thermal Efficiency up to 38.91 % and reduced Brake
In view of CO2 reduction, aimed to mitigate global warming, Fuel Economy (FE) is gaining a primary role in new specifications for engine lubricating oils. Not only oil rheological properties and friction reducer additives, but also all the components of the formulation, such as basestocks, viscosity modifier and additive package, are involved in achieving FE performances. Tribological tests were carried out in our labs to investigate the effect of detergent additives: in particular, the positive role of detergents based on Calcium salts ofcalixarenes, cyclic oligomers obtained from reaction of p-functionalized phenols with formaldehyde, emerged. This type of additives is particularly suitable for modern lubricants preserving aftertreatment efficiency as they are sulfur-free. In our labs both 400 TBN and 150 TBN Calcium calixarene-based detergents were synthetized and evaluated on MTM tribologicaltest where a lower friction coefficient is achieved in comparison to traditional detergents
A study was performed to compare the performance of small and large automotive, semi-metallic, friction pads, each manufactured with one of two different calcined coke fillers. Coke #1 is a conventional calcined petroleum coke, and Coke #2 a proprietary, calcined coke manufactured from a non-petrochemical feedstock and sold by Asbury Carbons under the trade name “EcoGreen”. The subject coke materials were fully characterized, physically and chemically. Chemical characterization included a modified TCLP leaching study performed on each coke. Both coke materials are similar in their respective physical properties, including morphology, hardness, and crush strength. However, there is a significant difference in the trace metal content of the two materials, with Coke #1 containing a higher content of sulfur, calcium, iron, nickel, and vanadium than Coke #2. Nickel, vanadium, and sulfur are considered potential environmentally hazardous substances. Initial friction element evaluation was
This SAE Recommended Practice describes an empirical method for determining the theoretical ash content of aviation piston engine lubricating oils by calculating the equivalent weight of metallic oxides formed at 775 °C based on the metallic elemental concentration. The calculation method of ash determination may be used as an alternate to ASTM D 482 for application to the standards for aviation piston engine lubricating oils
Engine oils have complex packages of additives aimed at improving their tribological properties. However, interactions between elements of these additives may hinder the cooling ability of these oils. The current article addresses the influence of the interaction between chemical elements of oil additives on the cooling capacity of oils for different wall superheats (0°C-150°C) and oil bulk temperatures (60°C, 100°C, and 150°C). A back-propagation neural network (BPNN) is used to conduct the present work. The NN is trained on experimental heat transfer data of five commercial engine oils. Enhancement intensity, interaction sensitivity, and interaction stability of additive elements are investigated for the range of element concentrations of the experimental dataset. The results show that, for a given element concentration, the interaction between all elements causes dissimilar heat flux enhancement/deterioration for different oils and also affects the behavior of oils at different wall
Renewable fuels have an important role to create sustainable energy systems. In this paper the focus is on biodiesel, which is produced from vegetable oils or animal fats. Today biodiesel is mostly used as a drop-in fuel, mixed into conventional diesel fuels to reduce their environmental impact. Low quality drop-in fuel can lead to deposits throughout the fuel systems of heavy duty vehicles. In a previous study fuel filters from the field were collected and analyzed with the objective to determine the main components responsible for fuel filter plugging. The identified compounds were constituents of soft particles. In the current study, the focus was on metal carboxylates since these have been found to be one of the components of the soft particles and associated with other engine malfunctions as well. Hence the measurement of metal carboxylates in the fuel is important for future studies regarding the fuel’s effect on engines. The first aim of this study was to create synthetic soft
Further fuel economy improvement of the internal combustion engine is indispensable for CO2 reduction in order to cope with serious global environmental problems. Although lowering the viscosity of engine oil is an effective way to improve fuel economy, it may reduce the wear resistance. Therefore, it is important to achieve both improved fuel economy and reliability. We have developed new 0W- 8 engine oil of ultra-low viscosity and achieved an improvement in fuel economy by 0.8% compared to the commercial 0W-16 engine oil. For this new oil, we reduced the friction coefficient under boundary lubrication regime by applying an oil film former and calcium borate detergent. The film former increased the oil film thickness without increasing the oil viscosity. The calcium borate detergent enhanced the friction reduction effect of molybdenum dithiocarbamate (MoDTC). By applying these technologies, an engine oil was developed which successfully achieved desired fuel efficiency and reliability
Investigations of the influence of calcium on pre-ignition in a two-stroke engine have shown that the lower the calcium concentration, the lower the frequency of pre-ignition. Pre-ignition problems can occur in small, air-cooled, two-stroke engines such as a chainsaw. In contrast, in a supercharged automobile engine, it has been reported that calcium, which is a detergent component in engine oil, causes low-speed pre-ignition. The oil for two-stroke engines also contains calcium and is mixed with the fuel and lubricated before being supplied to the combustion chamber. This makes, two-stroke engines more likely to be affected by oil components. Based on this, we investigated the influence of calcium on pre-ignition of a two-stroke engine. First, we investigated driving conditions in which pre-ignition is likely to occur, such as warming up the engine. Under this condition, oil with calcium concentrations ranging from 0 ppm to 1,500 ppm were tested at a mixing ratio of 2%. The results
This SAE Standard defines the requirements for an oil to be used in the SAE HS 806 Oil Filter Test Procedures
This specification covers a magnesium alloy in the form of sheet and plate
This specification covers a magnesium alloy in the form of plate
Several elements affect the structure of eutectic silicon in hypoeutectic aluminum alloys [1, 2, 3, 4]. Among them, calcium has been investigated to a lesser extent compared to the typically used sodium and strontium. In order to enhance the thermal fatigue strength of a small engine, the morphology of eutectic silicon in hypoeutectic aluminum-silicon alloys is controlled by the addition of calcium. In addition, the castability and mechanical properties are investigated. Hence, samples containing different amounts of calcium are prepared at different cooling rates during solidification. The results revealed that, with the increase in the calcium amount and the cooling rate, eutectic silicon exhibits a fine morphology in cross-sectional images. Particularly, with the addition of at least 62 mass ppm of calcium in a specific range of cooling rates, refined eutectic silicon is obtained. In order to clarify additional effects of the added calcium, the amount of dissolved gas, fluidity, and
Many studies on low speed pre-ignition have been published to investigate the impact of fuel properties and of lubricant properties. Fuels with high aromatic content or higher distillation temperatures have been shown to increase LSPI activity. The results have also shown that oil additives such as calcium sulfonate tend to increase the occurrence of LSPI while others such as magnesium sulfonate tend to decrease the occurrence. Very few studies have varied the fuel and oil properties at the same time. This approach is useful in isolating only the impact of the oil or the fuel, but both fluids impact the LSPI behavior of the engine simultaneously. To understand how the lubricant and fuel impacts on LSPI interact, a series of LSPI tests were performed with a matrix which combined fuels and lubricants with a range of LSPI activity. This study was intended to determine if a low activity lubricant could suppress the increased LSPI from a high activity fuel, and vice versa. The results
This specification covers a premium aircraft-quality steel in the form of bars, forgings, mechanical tubing and flash welded rings up to 5.000 inches (127.00 mm), inclusive, and stock for forging or flash welded rings
This specification covers a premium aircraft-quality steel in the form of bars, forgings, mechanical tubing, flash welded rings up through 6.000 inches (152.40 mm), and stock for forging or flash welded rings
This specification covers a premium aircraft-quality steel in the form of bars, forgings, mechanical tubing, flash welded rings up through 10.000 inches (254.00 mm) inclusive in diameter or least distance between parallel sides, and stock for forging or flash welded rings
Low speed pre-ignition (LSPI) is an undesirable combustion phenomenon that limits the fuel economy, drivability, emissions and durability performance of modern turbocharged engines. Because of the potential to catastrophically damage an engine after only a single pre-ignition event, the ability to reduce LSPI frequency has grown in importance over the last several years. This is evident in the significant increase in industry publications. It became apparent that certain engine oil components impact the frequency of LSPI events when evaluated in engine tests, notably calcium detergent, molybdenum and phosphorus. However, a close examination of the impact of other formulation additives is lacking. A systematic evaluation of the impact of the detergent package, including single-metal and bimetal detergent systems, ashless and ash-containing additives has been undertaken using a GM 2.0L Ecotec engine installed on a conventional engine dynamometer test stand. Consistent with previous
The effects of lubricant oil and fuel properties on low speed pre-ignition (LSPI) occurrence in boosted S.I. engines were experimentally evaluated with multi-cylinder engine and de-correlated oil and fuel matrices. Further, the auto-ignitability of fuel spray droplets and evaporated homogeneous fuel/oil mixtures were evaluated in a combustion bomb and pressure differential scanning calorimetry (PDSC) tests to analyze the fundamental ignition process. The work investigated the effect of engine conditions, fuel volatility and various lubricant additives on LSPI occurrence. The results support the validity of aspects of the LSPI mechanism hypothesis based on the phenomenon of droplets of lubricant oil/fuel mixture (caused by adhesion of fuel spray on the liner wall) flying into the chamber and autoigniting before spark ignition. Combustion bomb experiments confirmed that lubricant oil sprays have higher auto-ignitability than gasoline fuel components, and no particular effects of
Current and future diesel engine oil categories have specifications that impose limits on SAPS (Sulfated Ash, Phosphorous and Sulfur) levels that help to minimize accumulation of ash in the DPF originating from oil consumption in the engine. Metallic species in the oil formulation, mostly from detergents and anti-wear additives, have a significant impact on ash behavior when subjected to high temperatures during active regeneration of the filter. Certain compounds in the oil, especially derivatives of ZDDP (Zinc Dialkyl Dithiophosphate), interact with filter substrate and sinter at temperatures that the DPF is exposed to during active regeneration. This phenomenon of sintering or ‘ash wetting’ leads to ash-bridges in the DPF that result in reduction of soot storage capacity, higher back-pressure and possibly reduced active surface area for catalytic conversion of engine-out emissions. Changes in ash chemistry when subjected to high temperature transient events is irreversible and
This specification covers a special aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock
Friction performance is the result of the interaction between rotor and friction material surfaces. Kinetic energy has to be transformed into heat, plastic deformations, chemical reactions and wear debris. The later generates the formation of the so-called third body layer and its initiation, growth and degradation will generate the actual friction coefficient and vibrations behavior. Some raw materials seem to promote third body layer formation more than others. The composition of plateaus usually contains iron oxide, copper, carbon, silicon and calcium. Since copper free materials are under development, the importance of understanding the third body layer formation has become bigger. Promaxon® D is widely used in NAO non steel formulations. It is a calcium silicate with a special morphology that influences friction material at two levels: the macro -bulk- scale and the micro -surface- scale. Bulk effect is related to the volume and porosity degree of the friction material. This
Engine oil formulation is known to affect low speed pre-ignition (LSPI), which creates technical restrictions on downsized turbocharged engines. Calcium, which is used to ensure detergency and anti-rust performance, is reported to increase LSPI events. Therefore, new formulation technologies are needed to satisfy both LSPI prevention performance and other conventional performance areas. The authors focused on two approaches: enhancement of LSPI prevention performance by adding a booster component and substitution of calcium for a less reactive component to balance performance areas including LSPI prevention. We have verified the effectiveness of these approaches by increasing the dosage of molybdenum used as a friction modifier as well as replacing calcium detergent with a magnesium detergent. These formulation strategies can be applicable for future ILSAC GF-6 engine oil, where a specification for LSPI prevention performance is expected to be implemented
The use of Automatic Transmission Fluids (ATFs) with lower viscosity and excellent anti-shudder durability for wet clutch system will be effective for improving fuel saving performance in automatic transmissions. In this study, two ATF formulation techniques were examined. The first trial formulation is to improve fatigue life in gear components even if a lower viscosity ATF is used. The second one is to improve anti-shudder durability for wet lock-up clutch system in AT units. As to fatigue life performance, the relation between molecular weight of Viscosity Index Improver (VII) and film formation property in EHL contact regions were experimentally investigated. ATFs containing VIIs with lower molecular weight tend to increasing EHL film thickness, resulting in a longer gear pitting fatigue life. Calcium detergents and ashless friction modifiers in ATFs were found to give a great impact on the anti-shudder performance. The trial ATF containing these additives demonstrated 1.5 times
The effect of properties of lubricating oil on low speed pre-ignition (LSPI) was investigated. Three different factors of oil properties such as cetane number, distillation characteristics and Calcium (Ca) additive (with and without) are prepared and examined. Then actual engine test of LSPI was carried out to evaluate the effect and to clarify the mechanism and role of lubricating oil. Finally it is clarified that the oil cetane number and/or Ca additive strongly affect LSPI phenomena
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