scholarly journals Enhancing the Lubricity of Gas-to-Liquid (GTL) Paraffinic Kerosene: Impact of the Additives on the Physicochemical Properties

2020 ◽  
Author(s):  
Hani Ababnah ◽  
Nasr Mohamed ◽  
Hanif Choudhury ◽  
Lei Lei Zhang ◽  
Rafiqul Gani ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Physicochemical Properties ◽  
Negative Impact ◽  
Freezing Point ◽  
Ethyl Oleate ◽  
Heat Content ◽  
Wear Scar Diameter ◽  
Dual Nature ◽  
Fuel Jet ◽  
High Concentrations

Abstract Synthetic paraffinic kerosene (SPK) is an ultra-clean fuel with low aromatic content and negligible quantities of sulfur compounds . Although, SPK has a good potential to replace the conventional fuel Jet A-1 , it also has some deficiencies. One of them is the low lubricity compared to its conventional counterpart Jet A-1. To improve the lubricity of SPK, three selected additives have been mixed with SPK at different concentrations. The lubricity of the samples was determined experimentally and the samples that meet the industry specifications have been studied further. The effect of the additives on the physicochemical properties, such as, density, flash point, freezing point, viscosity, and heat content, were investigated. Linoleic acid was found to be an excellent lubricity improver even at a very low concentration and its negative impact on the other physicochemical properties was found to be insignificant. Ethyl oleate also demonstrated significant improvement in lubricity at low concentrations but had a negative impact on the fuel’s freezing point at high concentrations. Quinoline, at high concentrations, elevated the blend’s freezing point above the acceptable limits. In parallel to the experimental campaign, a pre-existing mathematical modelling tool was utilized to predict the properties of interest. The lubricity model was successfully introduced into the mathematical model in order to improve the capabilities of the model. Linoleic acid sample showed the best improvement in lubricity of SPK with wear scar diameter of 4 17 μm; well below the ASTM D7566 maximum limit of 850µm. The dual nature of this study facilitated the optimization of the physicochemical properties of the fuel samples.

scholarly journals Enhancing the Lubricity of Gas-to-Liquid (GTL) Paraffinic Kerosene: Impact of the Additives on the Physicochemical Properties

2020 ◽  
Author(s):  
Hani Ababnah ◽  
Nasr Mohamed ◽  
Hanif Choudhury ◽  
Lei Lei Zhang ◽  
Rafiqul Gani ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Physicochemical Properties ◽  
Negative Impact ◽  
Freezing Point ◽  
Ethyl Oleate ◽  
Heat Content ◽  
Wear Scar Diameter ◽  
Dual Nature ◽  
Fuel Jet ◽  
High Concentrations

Abstract Synthetic paraffinic kerosene (SPK) is an ultra-clean fuel with low aromatic content and negligible quantities of sulfur compounds. Although, SPK has a good potential to replace the conventional fuel Jet A-1, it also has some deficiencies. One of them is the low lubricity compared to its conventional counterpart Jet A-1. To improve the lubricity of SPK, three selected additives have been mixed with SPK at different concentrations. The lubricity of the samples was determined experimentally and the samples that meet the industry specifications have been studied further. The effect of the additives on the physicochemical properties, such as, density, flash point, freezing point, viscosity, and heat content, were investigated. Linoleic acid was found to be an excellent lubricity improver even at a very low concentration and its negative impact on the other physicochemical properties was found to be insignificant. Ethyl oleate also demonstrated significant improvement in lubricity at low concentrations but had a negative impact on the fuel’s freezing point at high concentrations. Quinoline, at high concentrations, elevated the blend’s freezing point above the acceptable limits. In parallel to the experimental campaign, a pre-existing mathematical modelling tool was utilized to predict the properties of interest. The lubricity model was successfully introduced into the mathematical model in order to improve the capabilities of the model. Linoleic acid sample showed the best improvement in lubricity of SPK with wear scar diameter of 417 µm; well below the ASTM D7566 maximum limit of 850 µm. The dual nature of this study facilitated the optimization of the physicochemical properties of the fuel samples.

A simulated mucus layer protects Lactobacillus reuteri from the inhibitory effects of linoleic acid

2013 ◽  
Vol 4 (4) ◽  
pp. 299-312 ◽  
Author(s):  
R. De Weirdt ◽  
E. Coenen ◽  
B. Vlaeminck ◽  
V. Fievez ◽  
P. Van den Abbeele ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Lactobacillus Reuteri ◽  
Close Contact ◽  
Mucus Layer ◽  
Inhibitory Effects ◽  
Intestinal Mucus ◽  
Gut Microbe ◽  
Protective Environment ◽  
Bacterial Cell Membrane ◽  
High Concentrations

Lactobacillus reuteri is a commensal, beneficial gut microbe that colonises the intestinal mucus layer, where it makes close contact with the human host and may significantly affect human health. Here, we investigated the capacity of linoleic acid (LA), the most common polyunsaturated fatty acid (PUFA) in a Western-style diet, to affect L. reuteri ATCC PTA 6475 prevalence and survival in a simulated mucus layer. Short-term (1 h) survival and mucin-agar adhesion assays of a log-phase L. reuteri suspension in intestinal water demonstrated that the simulated mucus layer protected L. reuteri against the inhibitory effects of LA by lowering its contact with the bacterial cell membrane. The protective effect of the simulated mucus layer was further evaluated using a more complex and dynamic model of the colon microbiota (SHIME®), in which L. reuteri survival was monitored during 6 days of daily exposure to LA in the absence (L-SHIME) and presence (M-SHIME) of a simulated mucus layer. After 6 days, luminal L- and M-SHIME L. reuteri plate counts had decreased by 3.1±0.5 and 2.6±0.9 log cfu/ml, respectively. Upon supplementation of 1.0 g/l LA, the decline in the luminal L. reuteri population started earlier than was observed for the control. In contrast, mucin-agar levels of L. reuteri (in the M-SHIME) remained unaffected throughout the experiment even in the presence of high concentrations of LA. Overall, the results of this study indicate the importance of the mucus layer as a protective environment for beneficial gut microbes to escape from stress by high loads of the antimicrobial PUFA LA to the colon, i.e. due to a Western-style diet.

scholarly journals Fatty Acids Profile, Physicalchemical Properties and Minerals with Quantify Indicador of Astrocaryum aculeatum Pulp Oil

2017 ◽  
Vol 9 (12) ◽  
pp. 352
Author(s):  
Bernardo M. Linhares ◽  
Ana Marcia D. C. Costa ◽  
Herliana D. F. Abreu ◽  
Ana Cristina G. Reis de Melo ◽  
Pedro R. E. Ribeiro ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Physicochemical Properties ◽  
Unsaturated Fatty Acids ◽  
Essential Fatty Acids ◽  
Saturated Fatty Acids ◽  
Fatty Acids Profile ◽  
High Concentrations ◽  
Astrocaryum Aculeatum ◽  
Air Circulation ◽  
Acid Index

The species Astrocaryum aculeatum (Arecaceae) is known in the Brazilian Amazon as tucumã, whose fruit is much appreciated by the population of the region, where its pulp, oleaginous, is the most consumed. Thus, the aim of this work was to perform a profile of fatty acids by GC-FID and minerals by ICP-OES of the oil of the pulp of the tucumã (A. aculeatum), as well as their physicochemical properties by 1H NMR. The fruits were collected in Alto Alegre city, Roraima, Brazil. These were taken to the laboratory, sanitized and removing your pulp, submitted to the oven with air circulation at 50 °C for 72 h, the dried pulps were milled and sieved between 20-40 mesh. The pulp oil extraction was realized in Soxhlet with hexane for 6 hours (yield of 54.7%). Were identified a total of 10 fatty acids, of these 23.8% are saturated fatty acids and 76.2% are unsaturated fatty acids: palmitic acid (10.4%), stearic acid (4.9%), oleic acid (64.2%), linoleic acid (11%) and linolenic acid (1%). The physicochemical properties have a pulp oil acid index of 0.31 mg KOH g-1, saponification of 190.39 mg KOH g-1, iodine index of 85.97 mg g-1. Minerals such as in their available forms K (70.05 mg L-1) Na (30.30 mg L-1), Ca (20.13 mg L-1) and P (20.07 mg L-1) were observed in high concentrations. The Amazon tucumã is an oleaginous that deserves our attention because it is composed of essential fatty acids that are beneficial to the human health.

scholarly journals The faint young Sun problem revisited with a 3-D climate–carbon model – Part 1

2014 ◽  
Vol 10 (2) ◽  
pp. 697-713 ◽  
Author(s):  
G. Le Hir ◽  
Y. Teitler ◽  
F. Fluteau ◽  
Y. Donnadieu ◽  
P. Philippot
Keyword(s):  
Radiative Forcing ◽  
General Circulation ◽  
Freezing Point ◽  
Climatic Factors ◽  
General Circulation Models ◽  
Companion Paper ◽  
One Dimensional ◽  
Carbon Dioxide Concentrations ◽  
Wide Range ◽  
High Concentrations

Abstract. During the Archaean, the Sun's luminosity was 18 to 25% lower than the present day. One-dimensional radiative convective models (RCM) generally infer that high concentrations of greenhouse gases (CO2, CH4) are required to prevent the early Earth's surface temperature from dropping below the freezing point of liquid water and satisfying the faint young Sun paradox (FYSP, an Earth temperature at least as warm as today). Using a one-dimensional (1-D) model, it was proposed in 2010 that the association of a reduced albedo and less reflective clouds may have been responsible for the maintenance of a warm climate during the Archaean without requiring high concentrations of atmospheric CO2 (pCO2). More recently, 3-D climate simulations have been performed using atmospheric general circulation models (AGCM) and Earth system models of intermediate complexity (EMIC). These studies were able to solve the FYSP through a large range of carbon dioxide concentrations, from 0.6 bar with an EMIC to several millibars with AGCMs. To better understand this wide range in pCO2, we investigated the early Earth climate using an atmospheric GCM coupled to a slab ocean. Our simulations include the ice-albedo feedback and specific Archaean climatic factors such as a faster Earth rotation rate, high atmospheric concentrations of CO2 and/or CH4, a reduced continental surface, a saltier ocean, and different cloudiness. We estimated full glaciation thresholds for the early Archaean and quantified positive radiative forcing required to solve the FYSP. We also demonstrated why RCM and EMIC tend to overestimate greenhouse gas concentrations required to avoid full glaciations or solve the FYSP. Carbon cycle–climate interplays and conditions for sustaining pCO2 will be discussed in a companion paper.

scholarly journals Formation and characterization of acid mine drainage in the Madzharovo ore field, Southeastern Bulgaria

2021 ◽  
Vol 35 (1) ◽  
pp. 41-50
Author(s):  
Svetlana Bratkova
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Negative Impact ◽  
Sulfide Minerals ◽  
Mining Areas ◽  
Acid Mine ◽  
Zinc Cadmium ◽  
High Concentrations ◽  
Cadmium Lead ◽  
The Impact

The formation of acid mine drainage (AMD) is a serious environmental problem in areas with mining and processing industries worldwide. Their generation is associated with chemical and biological processes of oxidation of sulfide minerals, mainly pyrite. Sources of AMD can be deposits of sulfide minerals and coal with a high content of pyrite sulfur, mining waste and some tailings. The impact of AMD on surface and groundwater in mining areas continues for decades after the cessation of extraction. An example of the negative impact of generated acid mine drainage on the state of surface waters is in the region of Madzharovo. Years after the cessation of mining, the waters at the discharge points "Momina Skala", "Harman Kaya" and "Pandak Dere" are characterized by low pH values and high concentrations of iron, copper, zinc, cadmium, lead and manganese.

scholarly journals Assessment of Physicochemical Properties and Heavy Metal Load in Soils of Ebocha Gas Flaring Site in Rivers State, Nigeria

2020 ◽  
pp. 1-9
Author(s):  
O. I. Achieche ◽  
O. O. Njoku ◽  
C. M. Duru ◽  
M. O. Nwachukwu
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Physicochemical Properties ◽  
Negative Impact ◽  
Soil Depth ◽  
Calcium Content ◽  
Gas Flaring ◽  
Metal Load ◽  
Acidic Nature ◽  
Rivers State

The negative impact of gas flaring on the environment cannot be overemphasised. This study assessed the effect of gas flaring on the physicochemical properties and heavy metal contents in soils of Ebocha gas flaring site in Rivers State. It involved the assessment of various distances from gas flaring point to 200 meters away (50 m, 100 m, 150 m, and 200 m) which represents the extent of gas flared pollution on soils to determine the physicochemical properties and heavy metal load. The gas flaring significantly decreased soil organic carbon and calcium content when compared with non-gas flaring polluted soils. Soil acidity increased, soil exchangeable ions decreased. N, P and K were altered in gas flared soils when compared to the controls. There were detrimental effects on soils physicochemical properties. Heavy metals observed were Cd (Cadmium), Ni (Nickel), As (Arsenic), Cr (Chromium), while Pb (Lead) was not detected. The concentration of heavy metals in gas flared soils decreases down soil depth from 0-15 cm to 45-60 cm respectively. The gas flaring extremely caused the acidic nature of gas flared soils. Coefficient of variation (CV) in percentage shows significant increase in acidic nature of the gas flared soils when compared with the control soils.

scholarly journals Estimation of Various Physicochemical Properties of Walnut Oil from Different Areas of Northern Kpk, Pakistan

2021 ◽  
Vol 65 (4) ◽  
Author(s):  
Yasir Uddin ◽  
Nasir Mehmood Khan ◽  
Farman Ali ◽  
Shujaat Ahamd ◽  
Zia Ullah Khan ◽  
...  
Keyword(s):  
Surface Tension ◽  
Oleic Acid ◽  
Linoleic Acid ◽  
Physicochemical Properties ◽  
Olive Oil ◽  
Food Processing ◽  
Juglans Regia ◽  
Acid Value ◽  
Walnut Oil ◽  
Iodine Values

Abstract. In this study, the physicochemical properties of walnut (Juglans regia L.) oils collected from different sites in Khyber PakhtoonKhwa (KPK), Pakistan were investigated. The obtained walnut oils showed variation in viscosity, surface tension, density, acid, saponification, and iodine values. The oil obtained from the Madyan (Sample E) showed the lowest density (0.981 g/cm3), surface tension (34.76×10-3 N/m), viscosity (15.0595 cp) saponification values 84.15 (mg KOH/g of oil) and acid value 3.5 (mg KOH per gram oil) amongst all. The physicochemical properties of all the oils were also compared to olive oil (standard) where sample E showed similarities in such properties compared to olive oil. Moreover, higher concentrations of oleic acid (41 %) and linoleic acid (9 %) were detected in the walnut oil of sample E in GC/MS analysis. The similarities of walnut oil obtained from Madyan to that of standard (olive oil) thus affirm it as best quality oil and suitable for food processing purposes.      Resumen. En este estudio se investigaron las propiedades fisicoquímicas del aceite de nuez (Juglans regia L.) recolectado de diferentes sitios en Khyber PakhtoonKhwa (KPK), Pakistán. Los aceites de nuez obtenidos mostraron variación en los valores de viscosidad, tensión superficial, densidad, acidez, saponificación e índice de yodo. El aceite obtenido del Madyan (Muestra E) mostró la menor densidad (0.981 g/cm3), tensión superficial (34.76 × 10-3 N/m), viscosidad (15.0595 cp), valores de saponificación 84.15 (mg KOH/g de aceite) y valor ácido 3.5 (mg KOH por gramo de aceite) entre otros. Las propiedades fisicoquímicas de todos los aceites también se compararon con el aceite de oliva (estándar); la muestra E mostró similitudes en las diferentes propiedades en comparación con el aceite de oliva. Además, se determinaron concentraciones más elevadas de ácido oleico (41 %) y ácido linoleico (9 %) en el aceite de nuez de la muestra E mediante el análisis GC/MS. Las similitudes del aceite de nuez obtenido de Madyan con el estándar (aceite de oliva) lo afirman como aceite de mejor calidad y adecuado para el procesamiento de alimentos.

scholarly journals Systematic Comparison of the Effect of Four Clinical-Grade Platelet Rich Hemoderivatives on Osteoblast Behaviour

2019 ◽  
Vol 20 (24) ◽  
pp. 6243 ◽  
Author(s):  
Tulio Fernández-Medina ◽  
Cedryck Vaquette ◽  
Sašo Ivanovski
Keyword(s):  
Cell Viability ◽  
Negative Impact ◽  
Early Time ◽  
Clinical Grade ◽  
Platelet Recovery ◽  
Migration Assay ◽  
Igf I ◽  
Clinical Considerations ◽  
High Concentrations ◽  
And Migration

Hemoderivatives have utilized in an empirical manner, driven by clinical considerations, leading to the development of a plethora of manufacturing protocols. The purpose of this study was to investigate the composition and bioactivity of four common clinical-grade hemoderivates prepared using standardised methods. Four different hemoderivatives were obtained from sheep blood and divided into two groups: A-PRF/i-PRF (fresh) and P-PRP/L-PRP (anticoagulated). Thrombus (CLOT) was used as a control. Thrombocyte quantification, growth factor composition (IGF-I, VEGF, PDGF-BB, BMP-2), cell viability, migration and mineralization assay were evaluated. Platelet recovery was superior for L-PRP followed by P-PRP. A significant cumulative release of IGF-I and PDGF-BB was noted for A-PRF and L-PRP groups at early time points. Similar release profiles of BMP-2 and VEGF were noted in all protocols. Cell viability and migration assay have demonstrated a detrimental effect when the concentration was ≥60%. Moreover, at Day 21, i-PRF have demonstrated superior mineralisation properties when compared to all groups. A negative impact of A-PRF was demonstrated at high concentrations. Despite its low content in growth factors, i-PRF was the best performing blood product for inducing osteoblast mineralisation, and therefore could be the candidate of choice for utilisation in bone tissue engineering applications.

scholarly journals Review on the Relationship Between Liquid Aerospace Fuel Composition and Their Physicochemical Properties

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Tinghao Jia ◽  
Lun Pan ◽  
Qing Liu ◽  
Yunming Fang ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
High Performance ◽  
Freezing Point ◽  
Operating Conditions ◽  
Hydrocarbon Fuels ◽  
Least Square ◽  
Fuel Properties ◽  
Molar Ratio ◽  
Fuel Composition

AbstractThe development of advanced air transportation has raised new demands for high-performance liquid hydrocarbon fuels. However, the measurement of fuel properties is time-consuming, cost-intensive, and limited to the operating conditions. The physicochemical properties of aerospace fuels are directly influenced by chemical composition. Thus, a thorough investigation should be conducted on the inherent relationship between fuel properties and composition for the design and synthesis of high-grade fuels and the prediction of fuel properties in the future. This work summarized the effects of fuel composition and hydrocarbon molecular structure on the fuel physicochemical properties, including density, net heat of combustion (NHOC), low-temperature fluidity (viscosity and freezing point), flash point, and thermal-oxidative stability. Several correlations and predictions of fuel properties from chemical composition were reviewed. Additionally, we correlated the fuel properties with hydrogen/carbon molar ratios (nH/C) and molecular weight (M). The results from the least-square method implicate that the coupling of H/C molar ratio and M is suitable for the estimation of density, NHOC, viscosity and effectiveness for the design, manufacture, and evaluation of aviation hydrocarbon fuels.

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