Densities and Viscosities of Oleic Acid at Atmospheric Pressure

The densities of oleic acid were measured over the temperature range from (293 to 459) K at atmospheric pressure using a densimeter based on the modified hydrostatic weighing method. The dynamic viscosities of the same oleic acid sample were measured using a capillary viscometer (VPZ-2 m) in the range from (293 to 363) K at atmospheric pressure. The combined expanded uncertainty of the density, atmospheric pressure, viscosity, and temperature measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.15%, 1.0%, 3.5%, and 15 mK, respectively. The values of uncertainty for density and viscosity include the effects of purity and calibration (total expanded uncertainty). These experimental data were used to develop wide-range correlations for the density and viscosity based on theoretically confirmed Arrhenius–Andrade and Vogel-Tamman-Fulcher (VTF) models. The value of the glass temperature ( T _g= 179.78 K.) for the oleic acid was estimated using the VTF parameters derived from the present viscosity measurements. To additionally validate the reliability of the measured density data, the same oleic acid samples were measured using the pycnometric method. The present study showed that the densities measured using the modified hydrostatic weighing densimeter (HWD) agree with the values obtained using the pycnometric method within 0.09% for Sample 1 and 0.25% for Sample 2.     

Chemical conversion of Calophyllum inophyllum oil into bio-hydrocarbons fuel over presulfided NiMo/Al2O3 catalyst

Chemical conversion of Calophyllum inophyllum oil (raw oil) over presulfided NiMo/Al₂O₃ catalyst was conducted to generate organic liquid products (OLP) containing bio-hydrocarbons (OLP-1). Reacted in ±273 mL autoclave for 200 minutes at 375°C, P_H2 of 1 MPa, and 1% of catalyst loading, the raw oil was converted into 78.24% OLP-1 with a heating value of 47.93 MJ/kg. The OLP was refined through distillation and grouped into boiling point (bp) range as 13.9% of gasoline (bp at 72.6°C-184°C), 10.8% of kerosene (bp at 184.1°C-235°C), 47.9% of diesel oil (bp at 235.1°C-400°C), and 26.3% of heavy fractions (bp at 400.1°C-688.5°C). Besides OLP-1, oxygenated compounds (OLP-2) were also contained as by-products. The catalytic reaction mechanism of C inophyllum oil was also confirmed using fatty acid model compounds. The OLP-1 mainly consisted of paraffinic hydrocarbons of C10-C18.     

Providing the stability of the coefficient of friction of a vehicle disk brake under extreme operating conditions

The authors propose a method of providing stability of the coefficient of friction of a disk brake. The method is based on the use of combination of friction materials in the force pattern of working elements of a disk brake. These friction materials interact with a brake disk and have individual level of loading. The article theoretically substantiates the possibility of the impact of the integral properties of a combination of friction materials involved in the force interaction on vehicle braking parameters. The reasonability of the proposed method is proved by the results of the experimental research. A brake-pad (lining) design has been developed to implement this method.     

Impregnation of carbonate rock by deasphalted oil with the use of a supercritical fluid impregnation process

The authors present the results of investigation and experimental implementation of several processes: production of heavy oil residue and its deasphaltizing and impregnation of carbonate rock with deasphalted oil. Heavy oil residue has been produced during fractionation of highly-vicious oil by steam-thermal method. Deasphaltizing of oil-residue and impregnation of carbonate rock are implemented with the use of extraction and supercritical fluid impregnation processes with propane-butane solvent.     

Extraction and characterization of highly purified collagen from bovine pericardium for potential bioengineering applications

Bovine pericardium is widely used as a raw material in bioengineering as a source of collagen, a fundamental structural molecule. The physical, chemical, and biocompatibility characteristics of these natural fibers enable their broad use in several areas of the health sciences. For these applications, it is important to obtain collagen of the highest possible purity. The lack of a method to produce these pure biocompatible materials using simple and economically feasible techniques presents a major challenge to their production on an industrial scale. This study aimed to extract, purify, and characterize the type I collagen protein originating from bovine pericardium, considered to be an abundant tissue resource. The pericardium tissue was collected from male animals at slaughter age. Pieces of bovine pericardium were enzymatically digested, followed by a novel protocol developed for protein purification using ion-exchange chromatography. The material was extensively characterized by electrophoresis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and infrared spectroscopy. The results showed a purified material with morphological properties and chemical functionalities compatible with type I collagen and similar to a highly purified commercial collagen. Thus, an innovative and relatively simple processing method was developed to extract and purify type I collagen from bovine tissue with potential applications as a biomaterial for regenerative tissue engineering.     

Mathematical modeling of filtering process of two-phase suspensions in tubular filters under nonisothermal conditions

The hydrodynamic conditions in tubular filter cells operating under nonisothermal conditions are studied. The equations of mechanics of heterogeneous media are used to describe the separation process of two-phase suspensions, which are written and simplified in the cylindrical coordinate system taking into account characteristics of the flow. The challenge is solved semi-analytically. Using the methods of surfaces of equal consumptions and Slezkin, numerical calculations on the constructed mathematical model are presented for particular implementations of the separation process.     

Comparison on efficiency factors of F and C types of fly ashes

Fly ashes are obtained from thermal power plants and they are pozzolanic materials, which can act as partial replacement material for both portland cement and fine aggregate. With their economical advantages and potential for improving fresh and hardened concrete performance, they have some benefits for using in concrete industry. In this study, the objective was to find the efficiency factors of Turkish C and F-type fly ashes and to compare their properties. Three different cement dosages were used (260, 320, 400 kg/m³), two different ratios (10% and 17%) of cement reduced from the control concretes and three different ratios (depending on cement reduction ratio) of fly ash were added into the mixtures. At the ages of 28 and 90 days, compressive strength, modulus of elasticity and ultrasound velocity tests were carried out. From the compressive strength results, the k efficiency factors of C and F-type fly ashes were obtained. As a result, it is seen that efficiency factors of the concrete produced by the replacement of F and C type fly ashes with cement increase with the increase in cement dosage and concrete age.     

Synthesis and characterization of CdS quantum dots with carboxylic-functionalized poly (vinyl alcohol) for bioconjugation

In the present research it is reported the synthesis and characterization of CdS nanoparticles (NPs) prepared using carboxylic-functionalized poly (vinyl alcohol) (PVA) as the ligand via aqueous route at room temperature and ambient pressure. Different molar concentrations of carboxylic-PVA and PVA were investigated aiming at producing stable colloidal systems. Carboxylic-PVA was conjugated with BSA (bovine serum albumin) and used as capping ligand in the preparation of CdS nanocrystals. UV-visible spectroscopy, photoluminescence spectroscopy, and transmission electron microscopy were used to characterize the kinetics and the relative stability of polymer-capped CdS nanocrystals. The results have clearly indicated that the carboxylic-functionalized PVA was much more effective on nucleating and stabilizing colloidal CdS nanoparticles in aqueous suspensions compared to PVA. In addition, the CdS nanocrystals were obtained in the so-called “quantum-size confinement regime”, with the calculated average size below 4.0 nm and fluorescent activity. Thus, a novel simple route was successfully developed for synthesizing nanohybrids based on quantum dots and water-soluble chemically functionalized polymers with incorporated carboxylic moiety with the possibility of direct bioconjugation.