Immersion In Oil Research Articles

Hagfish slime exudate stabilization and its effect on slime formation and functionality.

ABSTRACTHagfish produce vast amounts of slime when under attack. The slime is the most dilute hydrogel known to date, and is a highly interesting material for biomaterial research. It forms from a glandular secrete, called exudate, which deploys upon contact with seawater. To study slime formation ex vivo and to characterize its material properties, stabilization of the sensitive slime exudate is crucial. In this study, we compared the two main stabilization methods, dispersion in high osmolarity citrate/PIPES (CP) buffer and immersion in oil, and tested the influence of time, temperature and pH on the stability of the exudate and functionality of the slime. Using water retention measurements to assess slime functionality, we found that CP buffer and oil preserved the exudate within the first 5 hours without loss of functionality. For longer storage times, slime functionality decreased for both stabilization methods, for which the breakdown mechanisms differed. Stabilization in oil likely favored temperature-sensitive osmotic-driven swelling and rupture of the mucin vesicles, causing the exudate to gel and clump. Extended storage in CP buffer resulted in an inhibited unraveling of skeins. We suggest that a water soluble protein glue, which mediates skein unraveling in functional skeins, denatures and gradually becomes insoluble during storage in CP buffer. The breakdown was accentuated when the pH of the CP buffer was raised from pH 6.7 to pH 8.5, probably caused by increased denaturation of the protein glue or by inferior vesicle stabilization. However, when fresh exudate was mixed into seawater or phosphate buffer at pH 6-9, slime functionality was not affected, showing pH insensitivity of the slime formation around a neutral pH. These insights on hagfish exudate stabilization mechanisms will support hagfish slime research at a fundamental level, and contribute to resolve the complex mechanisms of skein unraveling and slime formation.

Soiling and corrosion behaviors on fluorinated anodized TiO2 surface infused by perfluoropolyether

Soiling and corrosion are severe problems in industrial process, such as fluid transportation in pipelines and heat exchange. Therefore, fluorinated TiO2 surface infused by liquid perfluoropolyether (PFPE) was successfully fabricated on titanium. The anti-soiling and corrosion resistance performance were investigated. TiO2 formation and fluorination were realized by anodization and chemical graft. PFPE was infused in fluorinated TiO2 via capillary force. The morphologies of TiO2 were characterized and liquid PFPE film equivalent thickness was measured. Corrosion resistance of the treated samples in 3.5 wt.% NaCl solution was investigated and its corrosion resistance was obviously improved. Contact angle hysteresis and sliding angle were measured. Compared with titanium, the PFPE infused fluorinated TiO2 surface presents lower contact angle hysteresis and sliding angle for various liquids. The necessity of immobilizing PFPE with surface roughening and fluorination was revealed. Soiling tests of the samples were proceeded by immersion in crude oil. Initially few crude oil soiling was adhered on the surface infused by PFPE and the good anti-soiling performance was kept about 120 min. In general, the lubricant infused fluorinated TiO2 surface displays outstanding corrosion resistance in 3.5 wt.% NaCl solution and effective anti-soiling for crude oil contamination.

Comparative evaluation of dissolution of a new resin-coated Gutta-percha, by three naturally available solvents

Introduction: The aim of this study was to evaluate and compare the effectiveness of eucalyptus oil, orange oil, and clove oil in dissolving resin-coated Gutta-percha (RCGP) cones.Materials and Methods: RCGP cones (EndoREZ,) (n = 70) and conventional GP cones (n = 70) with ISO size 25 and 4% taper were used for the study. Cones of each type were divided into three groups of twenty each, for immersion in eucalyptus oil, clove oil, and orange oil for 5 and 15 min immersion times. Ten GP cones from each group served as control and were immersed in distilled water. Each sample was weighed initially before immersing in the respective solvents. Cones were removed after specified immersion period, washed in distilled water, and allowed to dry. The samples were then re-weighed and statistical analysis was done.Results: Orange oil was most effective in dissolving both RCGP and conventional GP when compared to eucalyptus and clove oil. RCGP dissolved more readily than conventional GP in orange oil.Conclusion: Orange oil was the most effective solvent of EndoREZ RCGP and conventional GP among all tested solvents.

Wear and Corrosion of Cast Al Alloy Piston with and without Brake Oil

The effects of wear and corrosion of cast AA6061 aluminium alloy were studied with and without brake fluid using a wear jig while the corrosion rate was determined in brake fluid for 70 days under two experimental set-ups. The tests, yielded 0.00000123 g/mm2/min highest wear rate at 147000 wear cycles and 0.0334 mg/mm2/yr as the highest corrosion rate within the early 39th day of immersion in oil, the values being considered comparatively lower than those obtained for Al alloy in most common wet abrasion test and corrosion in aqueous solutions as previously reported in literature. The material loss rates to wear and corrosion were determined from the equations relating to wear and corrosion based on the ASTM designations. The results show that the combined actions of wear and corrosion contribute to the total loss of piston material immersed in brake oil. This is greater than either of their effects individually on cast Al alloy in the brake oil.

Crack initiation and propagation on the polymeric material ABS (Acrylonitrile Butadiene Styrene), under ultrasonic fatigue testing

Crack initiation and propagation have been investigated on the polymeric material ABS (Acrylonitrile Butadiene Styrene), under ultrasonic fatigue testing. Three controlled actions were implemented in order to carry out fatigue tests at very high frequency on this material of low thermal conductivity, they are: a) The applying load was low to limit heat dissipation at the specimen neck section, b) The dimensions of testing specimen were small (but fitting the resonance condition), in order to restraint the temperature gradient at the specimen narrow section, c) Temperature at the specimen neck section was restrained by immersion in water or oil during ultrasonic fatigue testing. Experimental results are discussed on the basis of thermo-mechanical behaviour: the tail phenomenon at the initial stage of fatigue, initial shear yielding deformation, crazed development on the later stage, plastic strain on the fracture surface and the transition from low to high crack growth rate. In addition, a numerical analysis is developed to evaluate the J integral of energy dissipation and the stress intensity factor K, with the crack length

Updates on chemistry and use of annatto (Bixa orellana L.)

<p>Food color is the first attribute evaluated by the consumer. Therefore, the food industry is concerned about the use of colorants in food materials to make them more attractive. Between the colorants used by the food industry, annatto is a raw material that allows the obtaining a large amount of natural pigments. The annatto dye is extracted from the outer layer of <em>Bixa orellana</em> L. seeds by immersion in alkaline solution, vegetable oil or organic solvents. In addition to the commercial preparations, a large amount of brazilian annatto seeds is used to prepare “colorífico”, a spice obtained from the mixture of pigment or grinded seeds with corn flour, vegetable oil and salt. Besides the bixin carotenoid, the seeds presents other components such as geranylgeraniol, with important pharmacological properties. The annatto seeds variability are influenced by conditions of post-harvest processing and the different cultivars used in industry. After the annatto processing, about 96% of waste are generated, which after dried and milled remain appropriate for reuse. During de pigment analysis in foodstuffs, the preparation techniques, the compounds separation and quantification requires, the use of standards with high purity and stability.</p><p> </p><p>DOI: 10.14685/rebrapa.v6i1.144</p>

Evaluation of Degradation of Structural Adhesive Joints in Functional Automotive Applications

Adhesive joints used in automobiles are subjected to very adverse operating conditions. Under these conditions, deterioration of the adhesive bond can be produced due to degradation both environmental and temperature, which leads to a decrease of the mechanical properties of the assembly over time. The present study analyzes the degradation experienced by adhesive joints of composite with aluminum, with two different adhesives (an epoxy and a polyurethane), when these are subjected, on one hand, a prolonged environmental exposure and, moreover, aging caused by high temperature and immersion in engine oil. Test results indicate that epoxy adhesive has better mechanical behavior than the polyurethane when the stays are prolonged weathering. Also, the epoxy adhesive also has good technical performance under the joint action of immersion in oil and heat, since this adhesive improves flexibility, and resistance to bending and tensile not experience significant changes during the 128hours of the test.

Swelling and mechanical properties of (acrylonitrile‐butadiene rubber)/(hydrogenated acrylonitrile‐butadiene rubber) blends with precipitated silica filled in gasohol fuels

This work studied the effects of hydrogenated acrylonitrile‐butadiene rubber (HNBR) and precipitated silica (PSi) loadings in acrylonitrile‐butadiene rubber (NBR) filled with 60 parts per hundred of rubber (phr) of carbon black (CB) for oil‐resistant seal applications in contact with gasohol fuel. The cure characteristics, mechanical properties, and swelling behavior of HNBR/NBR blends reinforced with PSi before and after immersion in ethanol‐based oils (E10, E20, and E85) were then monitored. This work studied the effects of PSi loading in rubber compounds on the mechanical properties of the rubber blends. The results suggested that the scorch time of CB‐filled NBR/HNBR was not affected by HNBR loading, but the cure time, Mooney viscosity, and torque difference increased with HNBR content. The swelling of the blends in E85 oil were relatively low compared with those in E10 and E20 oils. The recommended NBR/HNBR blend ratio for oil‐resistant applications was 50/50. Tensile strength and elongation at break before and after immersion in gasohol oils increased with HNBR loading, and the opposite effect was found for tensile modulus and hardness. PSi filler had no effect on scorch time, but decreased the cure time of the blends. The swelling level of the blends slightly decreased with increasing PSi content. The recommended silica content for optimum reinforcement for black‐filled NBR/HNBR blend at 50/50 was 30 phr. The results in this work suggested that NBR/HNBR blends reinforced with 60 phr of CB and 30 phr of silica could be potentially used for rubber seals in contact with gasohol fuels. J. VINYL ADDIT. TECHNOL., 22:239–246, 2016. © 2014 Society of Plastics Engineers

Technical Evaluation of Structural Adhesive Joints under Adverse Operation Conditions

This work analyzes the degradation of aluminum-composite adhesive joints under the action of water and motor oil. For this purpose, we have performed an accelerated ageing of the adhesive joint by immersion in water and oil. Likewise, we have evaluated the loss of mechanical properties that aging causes into adhesive joint. First, tests have been performed with bulk adhesive specimens (epoxy and polyurethane) immersed in water and motor oil during independent periods of time (1 at 128 days) in order to study the diffusion of water and motor oil into the adhesive. Second, we have evaluated the loss of mechanical properties that aging causes in the adhesive joint. Tests conclusions show that water degrades the adhesive more than motor oil. Additionally and under the action of water and motor oil, polyurethane adhesive joints retain their mechanical properties better than epoxy adhesive joints.

Durable Superhydrophobic/Superoleophilic Polyurethane Sponges Inspired by Mussel and Lotus Leaf for the Selective Removal of Organic Pollutants from Water

AbstractThe low stability of most superhydrophobic materials is one of the hurdles faced in terms of their practical applications. Inspired by mussel and lotus leaf, we report the fabrication of durable superhydrophobic/superoleophilic polyurethane (PU) sponges for the selective removal of organic pollutants from water. The superhydrophobic/superoleophilic PU sponges are prepared through in‐turn covalent modification of PU sponges with polydopamine, silver nanoparticles, and dodecyl mercaptan. The morphology and surface chemical composition of the sponges are characterized by scanning electron microscopy and X‐ray photoelectron spectroscopy. In addition, the wetting behaviors, stability, and oil/water separation performance of the superhydrophobic sponges are studied. The modified PU sponges show promising superhydrophobic and superoleophilic properties. The sponge has a water contact angle of about 155° and a shedding angle of approximately 3°, whereas the contact angle of oil is around 0°. In addition, the superhydrophobic coating on the PU sponge exhibits excellent mechanical, chemical, and environmental stability, for example, upon laundering, intensive scalpel scratching, long‐duration immersion in organic liquids and oils, and subjection to harsh temperatures and UV irradiation. Moreover, the superhydrophobic sponge can be used repeatedly for the selective and quick absorption of various insoluble organic pollutants (for example, petrol, crude oil, and chloroform) from water with high separation efficiency.

Magnetically driven super durable superhydrophobic polyester materials for oil/water separation

A facile approach for preparing magnetically driven durable superhydrophobic polyester materials is developed by simply dip-coating in a nanocomposite solution. The nanocomposite is prepared by the polymerization of tetraethoxysilane and n-hexadecyltriethoxysilane in the presence of the Fe3O4 nanoparticles. The coated magnetic samples exhibit excellent superhydrophobicity, superoleophilicity, and mechanical and chemical stability, owing to the tight binding of the nanocomposite on the polyester materials and the inherent stability of the polymerized organosilanes. The superhydrophobic materials can quickly absorb petrol, diesel and crude oil, and show very high selectivity in oil/water separation. In addition, the superhydrophobic materials could maintain their superhydrophobicity, oil absorption capacity and oil/water selectivity after a large amount of mechanical damage, 90 days of immersion in oil and ten cycles of absorption–desorption. Moreover, the coated sample can be magnetically driven to the polluted water zone using a magnet. Also, the facile approach can be easily scaled up for producing samples on a large scale, which makes it very promising for practical oil absorption.

Mechanical- and oil-durable superhydrophobic polyester materials for selective oil absorption and oil/water separation

The low stability and complicated fabrication procedures seriously hindered practical applications of superhydrophobic materials. Here we present a facile approach for preparing durable superhydrophobic polyester materials by dip-coating in a nanocomposite solution of polymerized tetraethoxysilane and n-hexadecyltriethoxysilane. The coated samples exhibit excellent superhydrophobicity, superoleophilicity, mechanical and chemical stabilities. This is attributed to the tight binding of the nanocomposite on the polyester fibers and the inherent stability of silicone. The coated samples can quickly absorb petrol, diesel and crude oil, and show very high selectivity in oil/water separation. In addition, the coated samples could maintain their superhydrophobicity, oil absorption capacity and oil/water selectivity after harsh mechanical damage, 90days of immersion in oils and ten cycles of absorption–desorption. Moreover, this approach is simple and can be easily scaled up for producing samples on a large size, which makes it very promising for practical oil absorption.

The effect of different organic solvents on the degradation of restorative materials.

Objective:To evaluate the solubility of three restorative materials exposed to the different endodontic solvents.Materials and Methods:The organic solvents eucalyptus oil, xylol, chloroform, and orange oil, with distilled water as the control group was utilized. The restorative materials light-cured resin (Filtek Z250/3M ESPE), light-cured-resin-reinforced glass ionomer (Riva Light Cure LC/Southern Dental Industries SDI]) and resin-modified glass ionomer (Vitremer/3M ESPE) were analyzed. A total of 50 disks containing specimens (2 mm × 8 mm Ø) were prepared for each of the three classes of restorative materials, which were divided into 10 groups (n = 5) for immersion in eucalyptus oil, xylol, chloroform, orange oil or distilled water for periods of either 2 min or 10 min. The means of restorative material disintegration in solvents were obtained by the difference between the original preimmersion weight and the postimmersion weight in a digital analytical scale. Data were statistically analyzed by two-way analysis of variance while the difference between the materials was analyzed by Student-Newman-Keuls test. The significance level set at 0.05.Results:Vitremer showed the highest solubility, followed by Riva LC, and these were statistically different from eucalyptus oil, xylol, chloroform, and distilled water (P < 0.05). Regarding the immersion time in solvents, there were no significant differences between the two tested periods (P > 0.05).Conclusions:The solvents minimally degraded the composite resin, although they did influence the degradation of both resin-modified glass ionomer resin and resin reinforced with glass ionomer.

Qualidade de ovos de codorna submetidos ou não a tratamento superficial da casca armazenados em diferentes ambientes

Com o objetivo de avaliar a qualidade de ovos de codornas japonesas tratados superficialmente, através de imersão em óleo mineral ou solução de própolis, foram conduzidos experimentos simultâneos em dois ambientes, sem refrigeração (Experimento 1) e com refrigeração (Experimento 2). Para cada experimento, foram selecionados 360 ovos íntegros distribuídos em delineamento inteiramente casualizado em esquema fatorial 3 x 5 (ovos não tratados; ovos imersos em solução de própolis e ovos imersos em óleo mineral, avaliados durante cinco tempos de armazenamento: 7; 14; 21; 28 e 35 dias), cada tratamento foi composto por seis repetições de quatro ovos cada. Os ovos apresentaram aumento da perda de peso, diminuição do peso específico e aumento do peso e do pH da gema, além de redução do pH do albúmen e de seu respectivo peso com o avançar do tempo de estocagem na ausência de refrigeração (Experimento 1), independente se receberam ou não tratamento na casca. Entretanto, o tratamento superficial com óleo mineral promoveu proteção contra essa perda progressiva de peso e diminuição do peso específico, tornando-as menos intensas com o avançar do período de estocagem sem refrigeração. No Experimento 2, a imersão dos ovos em óleo mineral conferiu menor perda de peso, maior peso específico, maior peso de gema e de albúmen durante o armazenamento sob refrigeração. A qualidade de ovos de codornas submetidos a tratamento superficial da casca por imersão em óleo mineral é preservada por até cinco semanas em diferentes ambientes, sem e com refrigeração.

In vitro effects of Salvia officinalis L. essential oil on Candida albicans

ObjectiveTo determine the anticandidal activities of Salvia officinalis L. (S. officinalis) essential oil against Candida albicans (C. albicans) and the inhibitory effects on the adhesion of C. albicans to polymethyl methacrylate (PMMA) resin surface. MethodsDisc diffusion method was first used to test the anticandidal activities of the S. officinalis L. essential oil against the reference strain (ATCC 90028) and 2 clinical strains of C. albicans. Then the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were determined by modified membrane method. The adhesion of C. albicans to PMMA resin surface was assessed after immersion with S. officinalis L. essential oil at various concentrations of 1×MIC, 0.5×MIC and 0.25×MIC at room temperature for 30 min. One-way ANOVA was used to compare the Candida cell adhesion with the pretreatment agents and Tukey's test was used for multiple comparisons. ResultsS. officinalis L. essential oil exhibited anticandidal activity against all strains of C. albicans with inhibition zone ranging from 40.5 mm to 19.5 mm. The MIC and MLC of the oil were determined as 2.780 g/L against all test strains. According to the effects on C. albicans adhesion to PMMA resin surface, it was found that immersion in the essential oil at concentrations of 1×MIC (2.780 g/L), 0.5×MIC (1.390 g/L) and 0.25×MIC (0.695 g/L) for 30 min significantly reduced the adhesion of all 3 test strains to PMMA resin surface in a dose dependent manner (P<0.05). ConclusionsS. officinalis L. essential oil exhibited anticandidal activities against C. albicans and had inhibitory effects on the adhesion of the cells to PMMA resin surface. With further testing and development, S. officinalis essential oil may be used as an antifungal denture cleanser to prevent candidal adhesion and thus reduce the risk of candida-associated denture stomatitis.

Effect of fly ash on thermal stability, flammability, oil resistance and transport properties of chlorinated styrene butadiene rubber composites

Fly ash (FA) can be used as a filler in rubber vulcanizates to get rid off their waste. Polymer composite based on chlorinated styrene butadiene rubber (CSBR)/containing varying amount of FA composites has been developed by melt compounding followed by dicumyl peroxide vulcanization. The influence of increased loading of FA on the cure characteristics, mechanical properties, thermal stability, flame and oil resistance has been investigated. The increase in FA loading in CSBR matrices has been found to accelerate the curing process up to 37% compared to unfilled sample. The uniform distribution of FA in CSBR has been confirmed by scanning electron microscopy, which also explained the improved mechanical properties, flame and oil resistance of the composites. The diffusion rate of aromatic hydrocarbon solvents through the composite film is minimum for composites with 30 phr of filler and the rate is increased with increasing the filler content. Activation parameters are estimated and the molecular mass is calculated using Flory–Rehner theory. The sorption data are used to estimate the enthalpy, entropy and free energy of mixing. Mechanical properties such as tensile strength, modulus and hardness of the samples decreased after immersion in ASTM oil and the decreasing trend is lower for 30 phr FA-filled samples.

Degradation of Adhesive Joints for Joining Composite Material with Aluminum under Immersion in Water and Motor Oil

Structural adhesive joints are adequate for joining aluminum with composite material (automotive, aeronautic, etc.). However, in many occasions, these adhesive joints are subjected to very adverse service conditions. This way, depending where they are, they must resist great humidity, oil projections, high temperatures, etc.For this cause, an appropriate operation of these adhesive joints requires know its behavior under these conditions. In line with this objective, present work analyzes the degradation that adhesive joints of composite material and aluminum experiences when they are immersed in water or motor oil. Also, the loss of mechanical properties originated by this degradation has been evaluated quantitatively by flexion tests.

Study of the compatibility of nitrile rubber with Brazilian biodiesel

Biodiesel is being proposed as an efficient replacement for fossil fuels. However, because of the difference in chemical compositions between biodiesel and fossil fuels, the resistance of polymeric materials to biodiesel may not be the same as that of fossil fuels. Thus, the aim of this work is to evaluate the resistance of different nitrile rubber (NBR) samples when in contact with biodiesel samples obtained separately from coconut oil and castor bean oil. The samples with lower acrylonitrile compositions (28 and 33%) exhibited low resistance to both pure biofuels. On the other hand, the mechanical properties of the NBR sample comprising 45% acrylonitrile appeared unchanged even after immersion in biodiesel oils.

Reduced Silicone Oil Adherence to Silicone Intraocular Lens by Surface Modification with 2-Methacryloyloxyethyl Phosphoryl-Choline

Purpose: to evaluate and compare the interaction of silicone oil–intraocular lens (IOLs) biomaterial in 2-methacryloyloxyethyl phosphoryl-choline (MPC) -modified IOLs and various widely used IOLs in vitro.Methods: Five groups of foldable IOLs, including 3-piece hydrophobic silicone IOLs, MPC-modified silicone IOLs, 3-piece hydrophilic hydrogel IOLs, one-piece hydrophilic acrylic IOLs and one-piece hydrophobic acrylic IOLs were photographed after immersion in silicone oil. The silicone oil coverage of the anterior and posterior surfaces of each IOL was measured using EPCO Image-analysis software. The hydrophilicity of the IOL surface was characterized by the water contact angle.Results: hydrophilic IOLs, such as MPC-modified silicone IOLs, hydrophilic acrylic IOLs and hydrogel IOLs having a lower contact angle exhibited less silicone oil adherence than hydrophobic IOLs, including both silicone IOLs and hydrophobic acrylic IOLs (p = 0.000, p < 0.05).Conclusions: MPC-modified hydrophilic silicone IOLs reduce silicone oil adherence, and thus may meet the need of a foldable IOL suitable for vitreoretinal patients.

Experimental study of the characteristics of solid fuel from fry-dried swine excreta

Swine excreta were dried by boiling via immersion in hot oil. In this method, moisture in the excreta is replaced with oil or evaporated by turbulent heat transfer in high-temperature oil. The dried excreta can be used in an incinerator like low-rank coal or solid fuel. Refined waste oil and B–C heavy oil were used for drying. Drying for 8min at 150°C reduced the water content of raw excreta from 78.90wt.% to 1.56wt.% (refined waste oil) or 1.62wt.% (B–C heavy oil) and that of digested excreta from 79.58wt.% to 3.40wt.% (refined waste oil) or 3.48wt.% (B–C heavy oil). The low heating values of the raw and digested excreta were 422kJ/kg and −2,713kJ/kg, respectively, before drying and 27,842–28,169kJ/kg and 14,394–14,905kJ/kg, respectively, after drying. A heavy metal analysis did not detect Hg, Pb, Cd, As, and Cr in the dried excreta, but Al, Cu, and Zn, which occur in the feed formula, were detected. Thermogravimetric analysis before and after drying revealed that emission of volatiles and combustion of volatiles and fixed carbon occurred at temperatures of 250–500°C when air was used as the transfer gas.