Single Oil Drop Research Articles

Towards harnessing hydrodynamic cavitation for producing emulsions: Breakage of an oil drop in a vortex based cavitation device

Emulsions are used as delivery vehicles for many active and functional chemical ingredients. There is an increasing need for developing new ways of producing emulsions on demand having desired critical quality attributes. Hydrodynamic cavitation (HC), which is a process of generation, growth and collapse of vapour cavities leading to intense localised shear and energy dissipation, offers an attractive platform for producing emulsions. In this work, we present experimental and computational results of a breakage of a single oil drop injected in a HC device. A single drop of oil was injected in a continuous stream of demineralised water flowing through a vortex based HC device. Tween 20 surfactant (2%) was used to prevent coalescence. The droplet size distribution (DSD) at the outlet of HC device was characterised using the imaging method. A detailed 3D computational model was developed to simulate turbulent cavitating flow through the considered HC device and resulting drop breakage and droplet size distribution. The developed model was used to quantitatively relate Sauter mean diameter (d32) and droplet size distribution (DSD) at the outlet with the operating parameters of the HC device. A single-pass through the vortex based HC device was able to bring down droplet size from ∼103 µm to ∼101 µm. The data and the model discussed in this work will provide a systematic basis for developing models, cavitation devices and operating protocols to produce emulsions with desired DSD.

Single oil drop breakage in water: Impact of turbulence level in channel flow

Single octanol droplet fragmentations in channel flow have been investigated by use of high speed imaging. The resulting raw data have been analyzed, interpreted and used to elucidate the fluid particle breakage phenomena, enabling improved understanding and motivating development of more universal population balance equation closures. The breakage kernel functions considered are the breakage time, the breakage probability, the average number of daughters and the daughter size distribution. These functions have been determined from the same set of data ensure consistency. The impact of the drop size and the turbulent energy dissipation rate on the different kernel functions were investigated. The breakage probability and average number of daughters functions correlate reasonably with the Weber number. Similarly, the breakage time correlates adequately with known model concepts. However, the correlations may not be considered universal as the parameter values obtained are not in agreement with values reported in the literature.

Aufstieg zur Energiemacht: Der sowjetische Weg ins Erdölzeitalter: 1930-er bis 1950-er Jahre

Aufstieg zur Energiemacht: Der sowjetische Weg ins Erdölzeitalter: 1930-er bis 1950-er Jahre

Coalescence and spreading of drops on liquid pools

HypothesisOil spills have posed a serious threat to our marine and ecological environment in recent times. Containment of spills proliferating via small drops merging with oceans/seas is especially difficult since their mitigation is closely linked to the coalescence dependent spreading. This inter-connectivity and its dependence on the physical properties of the drop has not been explored until now. Furthermore, pinch-off behavior and scaling laws for such three-phase systems have not been reported. ExperimentsWe investigate the problem of gentle deposition of a single drop of oil on a pool of water, representative of an oil spill scenario. Methodical study of 11 different n-alkanes, polymers and hydrocarbons with varying viscosity and initial spreading coefficients is conducted. Regime map, scaling laws for deformation features and spreading behavior are established. FindingsThe existence of a previously undocumented regime of delayed coalescence is reported. A novel application of the inertia-visco-capillary (I-V-C) scale collapses all experimental coalescence data on a single line while the early stage spreading is found to be either oscillatory or asymptotically reaching a constant value, depending on the viscosity of the oil drop unlike the well documented monotonic, power law late-time spreading behavior. These findings are equally applicable to applications like emulsions and enhanced oil recovery.

Akuakültür için Yeni Bir Tür: Sargoz Balığı (Diplodus sargus)

Sargoz balığı (Diplodus sargus) Akdeniz’de ticari değeri olan ve kontrollü şartlar altında yetiştiriciliği yapılabilecek deniz balığı türlerinden biridir. Bu çalışmada, sargoz balığı damızlıklarından döllenmiş yumurta, larva, yavru elde ederek türün kuluçkahane performansının araştırılması amaçlanmıştır. Çalışmada 8 adet dişi, 5 adet erkek damızlık balık kullanılmıştır. Örneklenen 1 g yumurta örneğinde 1248±13,47 adet yumurta olduğu tespit edilmiştir. Elde edilen 946,19±33,85 µm çapındaki yumurtaların 209,35±11,65 µm çapında tek yağ damlasına sahip oldukları gözlenmiştir. Yumurtaların 21,5±0,5°C’de ‰38 tuzlulukta 40. saatte açılmaya başladığı, açılma oranının ise %93,33±1,15, olduğu saptanmıştır. Ön beslemede yeşil su tekniği kullanılmıştır. Prelarvaların 5. günde %100 oranında yem almaya başladıkları tespit edilmiştir. Larvalar hava kesesi oluşumuna 6. günde başlamışlardır. Larvaların boyları ve ağırlıkları sırasıyla 55. günde 25,7±2,49 mm ve 255,8±6,6 mg olarak ölçülmüştür. Yaşama oranı %81,33±0,57 SGR oranı ise %10,79±0,12 olarak tespit edilmiştir.

Korea–Japan JDZ to End in Deadlock?: The Potential for Unilateral Korean Exploration and Exploitation

The Korea–Japan Joint Development Zone (JDZ) Agreement of 30 January 1974 was one of a number of innovative arrangements for cooperation in an overlapping maritime area. Nevertheless, four decades after its entry into force in 1978, the Agreement has not produced a single drop of oil. In contrast with Korea’s positive view on an oil discovery, Japan has held a negative stance since its concessionaires’ release of rights under the Agreement in 1992. Without Japan’s cooperation, the Agreement is a dead instrument. This article looks, from a Korean perspective, for the solutions whereby the Korea–Japan JDZ Agreement can operate.

Rapid hydrocarbon group-type semi-quantification in crude oils by comprehensive two-dimensional gas chromatography

Petroleum is the main source of energy used in the world. The oil industry faces challenges in trying to understand the chemical composition of crude oils, quantitatively and qualitatively. The application of specific and sophisticated techniques allows a detailed characterization and provides important information that impacts from the exploration to production, transportation, and crude oil refining. A set of twelve crude oil samples with different API gravity were analyzed via comprehensive two-dimensional (2D) gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS) aimed at the detection, identification and semi-quantification of hydrocarbon classes using extracted ion chromatogram (EIC) and total ion chromatogram (TIC). The use of the polar/non-polar column configuration provided better separation between the hydrocarbon classes which allowed the identification and semi-quantification of the same. Therefore, series of n- and iso-alkanes, alkyl-cyclohexanes, alkyl-cyclopentanes, alkyl-decalines, alkyl-naphthalenes, alkyl-phenanthrenes and alkyl-9H-fluorenes were characterized. In the present study, a semi-quantification approach to data assessment using TIC is proposed. Comprehensive evaluation provided the chromatographic fingerprint of each sample in a single analysis followed by the semi-quantification of the hydrocarbon classes. The oil samples presented completely different hydrocarbon class data, even when presenting similar API gravity values. Branched alkanes and n-alkanes were the major semi-quantified compounds, and branched alkane concentrations were higher than n-alkanes in the majority of samples. These results afford valuable information for the petrochemical industry. GC × GC-TOFMS was applied for speciation and group-type semi-quantification using a single oil drop without a fractionation or clean up step.

Toxicity of twenty-two plant essential oils against pathogenic bacteria of vegetables and mushrooms

ASBTRACTToxicity of twenty-two essential oils to three bacterial pathogens in different horticultural systems: Xanthomonas campestris pv. phaseoli (causing blight of bean), Clavibacter michiganensis subsp. michiganensis (bacterial wilt and canker of tomato), and Pseudomonas tolaasii (causal agent of bacterial brown blotch on cultivated mushrooms) was tested. Control of bacterial diseases is very difficult due to antibiotic resistance and ineffectiveness of chemical products, to that essential oils offer a promising alternative. Minimal inhibitory and bactericidal concentrations are determined by applying a single drop of oil onto the inner side of each plate cover in macrodilution assays. Among all tested substances, the strongest and broadest activity was shown by the oils of wintergreen (Gaultheria procumbens), oregano (Origanum vulgare), and lemongrass (Cymbopogon flexuosus. Carvacrol (64.0–75.8%) was the dominant component of oregano oils, while geranial (40.7%) and neral (26.7%) were the major constituents of lemongrass oil. Xanthomonas campestris pv. phaseoli was the most sensitive to plant essential oils, being susceptible to 19 oils, while 11 oils were bactericidal to the pathogen. Sixteen oils inhibited the growth of Clavibacter michiganensis subsp. michiganensis and seven oils showed bactericidal effects to the pathogen. The least sensitive species was Pseudomonas tolaasii as five oils inhibited bacterial growth and two oils were bactericidal. Wintergreen, oregano, and lemongrass oils should be formulated as potential biochemical bactericides against different horticultural pathogens.

Single Oil Drop Electrochemistry on a Screen‐Printed Electrode Surface

AbstractThe use of a contaminated single oil drop on a screen‐printed carbon electrode is described for the first time here. The simple methodology developed herein opens the possibility of conducting such measurements. R‐(+)‐limonene oil, some samples of which were contaminated with 4‐nitrophenol (4‐NP), was used as the oil phase, and BrittonRobinson (BR) buffer was used as the aqueous phase. An oxidation peak at approximately 0.8 V vs. Ag was obtained when the system comprised an oil/water interface. The charge transfer resistance decreased by a factor of approximately 7.1 when an interfacial system composed of two immiscible liquids was used as an electrochemical tool.

Comportamiento reproductivo del pez Opistognathus rosenblatti (Perciformes: Opistognathidae) en cautiverio

Reproductive behavior of Opistognathus rosenblatti (Perciformes: Opistognathidae) in captivity. The Blue Spotted Jawfish O. rosenblatti, is an endemic species from the Gulf of California, included in the local list of protected species. With few biological reports, this species is appreciated in the aquarium industry due to its coloration and digging behaviour, and has a considerable value. With the aim to generate valuable biological information, eight fishes were caught at Loreto Natural Marine Protected Area. Captured fishes were juveniles, and just three of them were kept in an aquarium conditioned with gravel, pieces of shells and coral as substrata. Temperature and photoperiod conditions were stable, and they were supplied with a variety of live and inert feeds. Fishes reached maturity in eight months, according to literature reports, displaying mature male courtship coloration and upward movements in the water column. Fishes spawned several times over more than two years in captivity. Presences of egg masses, or some evidence of egg shell or larvae, were registered in 50 occasions. Male took care of eggs in his shelter, but never in his mouth. Egg masses had an average of 3 592 eggs, with a hatching rate close to 99%. Eggs were apparently rounded having three diameter measurements with significant differences (1.17mm mean higher diameter, SD=0.054; 1.13mm mean lower diameter, 0.058; 0.99mm mean height, 0.045; n=125). Most of corion eggs had four, rarely six filaments; with a single oil drop (0.30mm mean diameter, 0.021, n=59). Incubation lasted 10.4 days (9-14), depending on water temperature (21.0-25.3°C). Egg hatching occurred after darkness, emerging newly hatched larvae of 4.51mm mean notochord length (0.082, n=30), with reserves exhausted, eyes pigmented and mouth opened, ready to eat. This study represents the first report on this species courtship displaying, spawning and some basic characteristics of eggs masses and larvae in captivity. Also, their flexibility and adaptability of individual behaviour to particular environment conditions, lead to consider worth their commercial culture, as already occur with other species of this family.

Application of the multicomponent lattice Boltzmann simulation method to oil/water dispersions

We study the propagation of acoustic fields in bounded, two-dimensional, mono-disperse oil/water emulsions using a carefully modified and appropriately calibrated single relaxation time multicomponent lattice Boltzmann equation simulation. Our model is a variant of an algorithm applying both interface forces based on macroscopic surface tensions and a kinematic condition for phase separation, adapted to allow sonic speed variations between its oil and water components. Appropriate second-order accurate acoustic boundary conditions are obtained from a node-based lattice closure with local mass conservation and applicability for varying fluid viscosities. Data from an example simulation of a single oil drop in water interacting with a generated standing acoustic wave are presented and, where appropriate, compared with empirical theories and analogous calculations for a solid object.

Lagrangian chaos and multiphase processes in vortex flows

We discuss experimental and numerical studies of the effects of Lagrangian chaos (chaotic advection) on the stretching of a drop of an immiscible impurity in a flow. We argue that the standard capillary number used to describe this process is inadequate since it does not account for advection of a drop between regions of the flow with varying velocity gradient. Consequently, we propose a Lagrangian-generalized capillary number C L number based on finite-time Lyapunov exponents. We present preliminary tests of this formalism for the stretching of a single drop of oil in an oscillating vortex flow, which has been shown previously to exhibit Lagrangian chaos. Probability distribution functions (PDFs) of the stretching of this drop have features that are similar to PDFs of C L. We also discuss on-going experiments that we have begun on drop stretching in a blinking vortex flow.

Transfer of orlistat through oil–water interfaces

The transfer of radiolabelled orlistat ([ 14C]orlistat), a potent gastrointestinal lipase inhibitor, through an oil–water interface from a single oil droplet to an aqueous phase was investigated, using an oil drop tensiometer. The absolute transfer fluxes were found to be very low, even in the presence of micellar concentrations of bile salts, which increased their values from 0.2 to 2.5 and 6.5 pmol cm −2 min −1 in the presence of 0, 4 and 15 mM NaTDC, respectively. Adding either a lipid emulsion or pure human pancreatic lipase (HPL) or human serum albumin or β-lactoglobulin had no effect on the flux of transfer of orlistat. The presence of colipase or a mixture of colipase and HPL was found, however, to reduce the flux of orlistat transfer, probably because it partly covered the single oil drop surface, even in the presence of bile salts. Using a finely emulsified system, we investigated the partitioning of orlistat between the aqueous and oil phases, in the absence or presence of bile salts above their CMC (4 mM NaTDC, final concentration). Under these emulsified conditions, orlistat was found to be mostly associated with the oil phase, since more than 98.8% of the total radioactivity was recovered after decantation with the oil phase. The low transfer rates of orlistat, as well as its partitioning coefficient between the oil and the aqueous phases, should help us to better understand the inhibitory effects of orlistat on lipid digestion in humans.

Spreading of oil from protein stabilised emulsions at air/water interfaces

Spreading of a drop of an emulsion made with milk proteins on air/water interfaces was studied. From an unheated emulsion, all oil molecules could spread onto the air/water interface, indicating that the protein layers around the oil globules in the emulsion droplet were not coherent enough to withstand the forces involved in spreading. Heat treatment (90 °C) of emulsions made with whey protein concentrate (WPC) or skim milk powder reduced the spreadability, probably because polymerisation of whey protein at the oil/water interface increased the coherence of the protein layer. Heat treatment of emulsions made with WPC and monoglycerides did not reduce spreadability, presumably because the presence of the monoglycerides at the oil/water interface prevented a substantial increase of coherence of the protein layer. Heat treatment of caseinate-stabilised emulsions had no effect on the spreadability. If proteins were already present at the air/water interface, oil did not spread if the surface tension ( γ) was <60 mN/m. We introduced a new method to measure the rate at which oil molecules spread from the oil globules in the emulsion droplet by monitoring changes in γ at various positions in a ‘trough’. The spreading rates observed for the various systems agree very well with the values predicted by the theory. Spreading from oil globules in a drop of emulsion was faster than spreading from a single oil drop, possibly due to the greater surface tension gradient between the oil globule and the air/water interface or to the increased oil surface area. Heat treatment of an emulsion made with WPC did not affect the spreading rate. The method was not suitable for measuring the spreading rate at interfaces where surface active material is already present, because changes in γ then were caused by compression of the interfacial layer rather than by the spreading oil.

Yolk mobilization in perch, Perca fluviatilis L., embryos

During embryogenesis of the perch, Perca fluviatilis L., a gradual proteolysis of yolk proteins was revealed by SDS-PAGE and immunoblotting and was comparable to other teleosts. A 118 kDa polypeptide was processed in two 96 and 18 kDa descendants; further proteolysis produced two peptides of 64 and 31 kDa. Ultrastructure and immunocytochemistry were used to compare electrophoresis patterns with morphological changes in the developing embryo and to localise yolk proteins in embryonic cell layers. In contrast to most other freshwater teleost, in spawned eggs of the perch yolk spheres fused together forming a homogenous yolk mass; lipid droplets formed a single oil drop on top of the egg. Combination of electrophoresis data and light and electron microscopical observations suggested a specific and parallel mobilization of yolk and lipid. In addition, yolk absorption by the yolk syncytial layer was observed. Numerous yolk platelets were found in the yolk syncytial layer and, in later stages of embryogenesis, also in the inner cell mass, but never in the cells of the enveloping layer.

Spawning migration of moki (Latridopsis ciliaris) off eastern New Zealand

Abstract Commercial fishing statistics for 4 east coast ports, Gisborne, Napier, Wellington, and Kaikoura, were analysed for seasonal changes in moki abundance. Moki from commercial catches at Gisborne and Kaikoura were sampled for sex, body and gonad weight, and reproductive status. A small‐scale tagging programme was carried out at Kaikoura. Commercial catches of moki were strongly seasonal, with abundance peaks occurring in August‐September at Gisborne, June‐July and September‐October at Napier, September‐October at Wellington, and May‐June and October at Kaikoura. Moki were resting or developing reproductively in May‐June at Kaikoura, ripe and spawning in August‐September at Gisborne, and spent in October at Kaikoura. At Kaikoura the sex ratio in catches was 1: 1 during both abundance peaks, but at Gisborne males outnumbered females 4: 1 in early August, with the sex ratio declining to 1: 1 by mid September. Moki eggs are smooth and spherical with a non‐segmented yolk and a single oil drop. They can be distinguished from copper moki (L. forsteri) eggs on the basis of oil drop diameter. Moki tagged at Kaikoura in May 1979 were recaptured at Gisborne (2 fish), Napier (1), and Kaikoura (9). One of the fish recaptured at Gisborne had travelled 540 km in 108 days (5.0 km/day) and the Napier fish 430 km in 65 days (6.6 km/day). Recaptures at Kaikoura showed that both peaks of abundance comprised the same fish. The results suggest the existence of a single stock of moki on the east coast of New Zealand. The fish make an annual spawning migration, swimming north from Kaikoura in May‐June, reaching Gisborne to spawn in August‐September, and then swimming south, passing Kaikoura again in October.