Esters from castor oil functionalized with aromatic amines as a potential lubricant

Vegetable oils are very promising alternatives to fossil lubricants due to their abundance, low cost, excellent performance, and environmental friendliness. Due to its multifunctional structure, castor oil is an excellent precursor in the synthesis of new biolubricants. However, it showed poor thermal-oxidative stability and a higher pour point. This study used castor oil fatty acids prepared by transesterification (EHRO), epoxidation (TEPO), and oxirane ring opening with the aromatic amines aniline (ANIL) and p-anisidine (ANIS). The chemical structure of these oils was verified by ¹H and ¹³C NMR analysis, and mass spectrometry. Measurements show that the presence of an aromatic amine increases the viscosity resulting in 172 (ANIL) and 199 (ANIS) cSt at 40°C, but reduces viscosity index to 16 and 1, respectively. In addition, the amine groups can scavenge radicals increasing their thermal and oxidative stability. These products do not oxidize copper, and tribological analysis reveals that ANIS has the lowest torque with wear equivalent to commercial mineral lubricant NH-140.     

The Formation of a 12-Hydroxystearic Acid/Vegetable Oil Organogel Under Shear and Thermal Fields

External laminar oscillatory shear applied during crystallization in combination with different temperature fields was used to modify the microstructure and physical properties of edible oil organogels. Crystallization at a high cooling rate (30 °C/min) resulted in a spherulitic microstructure with a higher oil-binding capacity, lower storage modulus and lower yield stress compared with a material (with a fibrillar microstructure) crystallized at a slow cooling rate (1 °C/min). The application of an oscillatory shear resulted in the formation of novel microstructures depending on the cooling regime used. The application of an oscillatory shear (strain > 500 % and frequency = 1 Hz) resulted in the thickening of fibers observed in the slow-cooled material and an increased incidence of spherulite nucleation in the rapidly cooled material. Increasing the frequency of the oscillatory shear applied did not change the microstructure for the slow-cooled gel but further increased the incidence of nucleation for the rapidly cooled gel. The application of controlled-strain oscillatory shear to the crystallizing gel at either cooling rates resulted in an oily and very soft, paste-like material. This material had a lower storage modulus and poorer oil-binding capacity compared with the same gel crystallized statically. Reduction of the oscillatory strain from a maximum of 1500 to 500 % moderately mitigated the loss of mechanical properties and oil-binding capacity although these properties were in no way comparable to those obtained from static crystallization. The study shows that the application of oscillatory shear and different cooling regimes can be used to tailor a crystalline organogel. However, the application of continuous shear must be done with care as application of excessive shear can result in a complete breakdown in gel structure and large amounts of oil loss.     

Technology of welding and properties of welded joints of new bainitic and martensitic steels with creep-resistant steels

This paper shows the results of welding tests used so far on high-temperature creep resistant steels and new bainitic and martensitic steels. The positive results of this research allowed the elaboration of a welding procedure specification that was ultimately approved by TÜV. This then allowed the SEFAKO Company to attempt welding of the latest generation boiler steels for use under heavy conditions.     

Influence of post-weld heat treatment (PWHT) on the structure and properties of welded joints of chromium–nickel stainless steel with soft martensite

This paper reviews the results of investigations on how post-weld heat treatment (PWHT) influences the hardness and microstructures of welded joints in stainless steel X3Cr-NiMo 13-4. It is known that welding leads to high segregation of components in the solidification process, which has an influence on phase transitions in PWHT. The investigated steel has a very narrow PWHT range, about 600–620°C, which provides optimum levels of hardness and toughness. Excessive annealing temperature leads to decreased toughness, which in turn causes exceeding of the A_c1 temperature in the segregation range, which then leads to increased ‘fresh’ martensite content.     

Impact sensitivity of nitroglycerin

Abstract

The impact sensitivity of liquid nitroglycerin, 50% initiation level, was observed to be near 1.8 kg?cm or 3.3 × 10³ j/m². The impact sensitivity of solid nitroglycerin, 50% initiation level, was observed by extrapolation to be near 200 kg?cm or 4.4 × 10⁵ j/m². The impact sensitivity of a mixture of solid and liquid NG was observed to be comparable to solid NG at the two stimulus levels tested. Thus, the presence of solid nitroglycerin reduces the impact sensitivity of liquid nitroglycerin.

The 50% initiation level for Class A cyclo-tetra-methylenetetranitramine was observed to be near 150 kg?cm or 3.3 × 10⁵ j/m² using the same instrument.     

Identification and characterization of surface lipid components of the dried-bean beetle Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae)

The dried-bean beetle Acanthoscelides obtectus is a major post-harvest pest, which can cause up to 30% losses from dry-stored beans. For the use of microbial agents for biocontrol of A. obtectus, it is of importance to identify cuticular lipids of this pest, if we are to understand the factors responsible for preferential adhesion or selective repulsion of entomopathogenic fungi that are potentially useful for biocontrol.The cuticular lipids of adult A. obtectus of both sexes were found to consist of hydrocarbons, aldehydes, methyl- and ethyl-esters of fatty acids, triacylglycerols, free fatty acids, alcohols and sterols. All the fatty acids identified in this study were found in both ether extracts and dichloromethane extracts. The dominant fraction of all the lipids isolated from this species consisted of C_16:0, C_18:0, C_18:1, C_18:2 and C_18:3 compounds. Males and females contained similar amounts of hexadecanoic acid, but there was a significant difference between the total amounts of C_18:0, C_18:1 and C_18:2 acids in the two groups. We have also successfully identified one of the sesquiterpenes present in the cuticle as α-farnesene.     

Metal–support interactions on rhodium model catalysts

Metal–support interactions on supported rhodium catalysts were studied by using specially prepared Rh/TiO₂/Mo model systems. For their characterization and the analysis of modifications due to various heat treatments several surface analytical methods were applied: low-energy ion scattering, X-ray photoemission spectroscopy and thermal desorption spectroscopy. Heating in ultrahigh vacuum to 670 K leads to Rh agglomeration followed (above 720 K) by encapsulation including the formation of reduced titanium oxide species. These morphological and chemisorption changes are reversible upon reoxidation and low-temperature reduction and thus exhibit the characteristic features of strong metal–support interactions. For the effective mechanism a reaction is suggested that involves oxygen chemisorption on the Rh clusters and partial reduction of the surrounding support oxide.     

Satiety role of the small intestine examined in sham-feeding rhesus monkeys.

Conducted 4 experiments with 4 male rhesus monkeys in which food was diverted from the stomach, the small intestine, or both. Results demonstrate that (a) food acting at the pregastric level was not sufficient to produce normal-sized meals, (b) accumulation of food in the small intestine was necessary to produce normal-sized meals, and (c) a potent preabsorptive or postabsorptive satiety signal originated at the intestinal level. It is concluded that this unidentified satiety signal is sufficient to elicit satiety, can be dissociated from gastric emptying, and does not require the presence of gastic distention to operate. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)