Browse Topic: Calcium
In research published in Cell Reports Physical Science, the NJIT team led by Professor Dibakar Datta successfully applied generative AI techniques to rapidly discover new porous materials capable of revolutionizing multivalent-ion batteries. These batteries, using abundant elements like magnesium, calcium, aluminum, and zinc, offer a promising, cost-effective alternative to lithium-ion batteries, which face global supply challenges and sustainability issues.
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.
Scientists have developed a ceramic-based ink made of calcium phosphate to 3D print bone parts complete with living cells that could be used to repair damaged bone tissue. The 3D printer method is ceramic omnidirectional bioprinting in cell-suspensions (COBICS), which enables surgeons to print bonelike structures that harden in a matter of minutes when placed in water. The material can be created at room temperature — complete with living cells — and without harsh chemicals or radiation.
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 Specific Fuel Consumption up to 35 %. Also, HC, CO, NOx and smoke emissions reduced up to 36.36 %, 33.33 %, 49.35 % and 25.13 % with the addition of calcium oxide Nano fluid. The in cylinder pressure and heat release rate increased for biodiesel and its Nano additive when compared to diesel fuel.
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. Also the SRV tribological tests confirmed a positive effect of calixarenes detergents. A preliminary engine test evaluation on Sequence VIE provided a further confirmation of the good behavior of calixarenes-based detergents jointly with an amino-type friction reducer: a FE result with a pass margin that amounts to one third of the ILSAC GF-6A limit for SAE 0W-20 (that is 3.8%) was achieved with the use of a fully calixarene-based detergent system. The use of calixareneoverbased (OB) detergent in combination with neutral Calcium sulfonates, provided a slightly lower performance at Sequence VIE test. In M111FE tests, the SAE 0W-20 oil provided over 4% FE improvement, clearly higher than the ACEA C5 limit (that is 3%), while both 5W-30 at low (2.9 mPa.s) and high (3.5 mPa.s) HTHS viscosity fulfilled the ACEA C2 limit of 2.5%. The same oils showed robust FE performances on chassis-dyno tests according to NEDC cycle where the candidate oils 0W-20 and 5W-30 almost doubled, on the average, the FE limits of respective Mercedes-Benz specs. Finally, the mixed system containing the Calcium calixarene OB detergent was positively tested in terms of oxidation, deposits, wear, sludge, as well as emerging issues like low speed pre-ignition and air entrainment. All the tests were run accordingly with ACEA C5/C2/C3, MB 229.71/61/52 and API SN+ specifications.
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 performed using the J661 Brake Lining Quality Test Procedure (Chase Test). Based on Chase test qualification, complete inertial dynamometer testing (SAE J2522) was also performed. Each coke material was formulated into two different automotive brake elements: a small vehicle pad with a Toyota rotor, and a large vehicle pad using an AC Delco rotor. The friction formula utilized is a commercial, proprietary mixture. Test results show that the friction materials, each containing one of the subject coke fillers, behaved similarly. Overall, test results indicate that road testing and further evaluation of Coke #2, an environmentally sustainable, low metals and low sulfur coke, by friction manufacturers is warranted.
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 superheats and bulk temperatures. Some additive elements such as sodium, molybdenum, and boron are effective, sensitive, and stable to thermal interaction with other elements in oils, whereas calcium is the least sensitive element. Statistical analysis shows that some elements are less stable than others. In particular, silicon and phosphorous might change their effects from thermally antagonistic to synergetic elements.
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. The developed oil also met the new JASO GLV-1 specification.
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 particles from biodiesel. Accelerated aging of fuels with different contaminations such as engine oil and calcium oxide were used to create the synthetic soft particles. The precipitates were collected and analyzed with different techniques such as FTIR and GC-MS, to identify the main components which were then compared with the results of the previous study. Following this, specific attention was given to calcium methyl azelate as it was shown to be found in field fuel filters. A method using GC-MS was developed to be able to estimate the amount of soft particles by measuring calcium methyl azelate. The specified method proved to be adequate for future studies to evaluate the filtration efficiency of different filter materials against soft particles.
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 show that the lower the calcium concentration, the lower the incidence rate of pre-ignition. Which could also occur at 0 ppm. The incidence rate was 4.6% at 1,500 ppm and 2.3% at 0 ppm.
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 porosity defects are evaluated. The amount of dissolved gas and the fluidity do not change in the range of the investigated calcium amounts. However, the sizes of each of the shrinkage porosities decrease and the region where porosities generated is spread, with spread-out regions. The sample strength with refined eutectic silicon is evaluated by tension and thermal fatigue tests. Refined samples exhibit greater elongation and thermal fatigue strength compared with those of eutectic silicon with a coarse morphology. The addition of calcium leads to the effective enhancement of the mechanical properties of hypoeutectic aluminum-silicon alloys.
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 showed that a low activity fuel was insensitive to the lubricant used in the test, while a high activity fuel could be moderated by a low activity lubricant. The combination of a high activity fuel and high activity lubricant, as expected, yielded a large number of LSPI events. These results help to understand how formulation changes to the lubricant or to the fuel may impact the other fluid, particularly with respect to regional variations in fuel specification and in lubricant additive standards.
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 reports, the detergent system was found to have the largest impact on LSPI frequency. Furthermore, once a balanced detergent system was identified and its LSPI impact was minimized, the effect of other additives, ash-containing as well as ashless, became apparent. In order to develop a robust additive package that maintains performance in critical bench and engine tests while offering optimal LSPI protection, consideration must be given to the impact of all lubricant additives not simply the detergent type and treat rate.
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 lubricant additives on ignitability were observed. However, under the conditions of the PDSC test, it was shown that the oxidative stability of fuel/oil mixtures is lower as the fuel/oil ratio is increased, and higher levels of calcium lubricant additives can bestow enhanced oxidation stability on some mixtures. These results indicate that calcium may promote autoignition during combustion under preheated and premixed mixture conditions, even though it plays an active role in preventing liquid phase oxidation. From this analysis, it is hypothesized that in real engines, certain lubricant additives, initially preheated by the autoignition of oil derived droplets, may give a greater propensity for subsequent flame propagation and abnormal combustion phenomena.
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 necessitates wet cleaning of the DPF to recover most of the filter performance. Ash samples were collected from field returned DPF’s that were categorized into line-haul and a mix of ‘stop and go’ duty-cycles; these trucks had two different heavy-duty diesel engine types. Several techniques for materials and chemical characterization such as high-temp XRD (X-ray Diffraction), Raman Spectroscopy, ICP-OES, SEM-EDS amongst others were employed in the current study for an in-depth understanding of the composition, phase transition and crystal lattice structure of the samples. Additionally, DPF ash from two different oil formulations were evaluated for their wetting behavior on the filter substrate and changes in ash composition were documented. Ash that was rich in phosphorous compounds exhibited phase transitions which were different from the ash that was rich in calcium compounds. Crystallographic planes from phosphate compounds were identified and correlated with oil formulations and vehicle operating conditions. Data generated in this study provides insights into ash morphology, chemistry and compositional changes when subjected to high temperatures in the DPF operating range. Analysis of ash from field returned DPF’s can be helpful in understanding filter operating history (regeneration conditions, duty cycles, engine oil type etc.), which then could be used as inputs for recommending filter service intervals, specific cleaning techniques and even DPF calibration based on mileage and duty-cycles.
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 affects the elastic modulus and vibration adsorption. The micrometric effect is related to the third body layer. When Promaxon® D is combined properly with an anchoring material (i.e. a fibre) it can promote the initiation and stabilization of the third body layer. As a result friction coefficient stabilization and wear will be improved. Wear is also directly related to noise as proposed by Lee et al [15]. This paper deals with the understanding of the importance of calcium silicate morphology for the bulk properties and in the third body layer formation. It demonstrates how the raw materials morphology, regardless of its chemical composition, plays an important role at macro and micro level in NAO non steel materials.
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 longer anti-shudder durability compared with a commercial ATF.
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