• Explosives and Blasting
• /
• v.30 no.2
• /
• pp.52-58
• /
• 2012

A TBM launching shaft in DTL2 Contract 915 site is located in a typical hard Bukit Timah granite formation and lots of blasting work is required for shaft sinking. The original blast design used the electric detonator and ANFO blasts consisting of 30 holes per one blast with 1.5 m depth of drilling hole. However, significant delay of work and poor progress were expected due to the limitation of the number of blasting hole and strict vibration regulation on retaining systems. To overcome such constraints, an efficient new blasting method which can improve productivity and satisfy vibration limit was required. The revised blast design, using triple-deck blasts with electronic detonators and cartridge emulsion explosives, gives better construction performance and can reduce construction time. Such a new blasting technique can be effectively used for similar underground projects in the future where the volume of rock blasting is significant.

• Polymer(Korea)
• /
• v.36 no.2
• /
• pp.177-181
• /
• 2012

This study presents the preparation of double emulsions in a poly(dimethylsiloxane) (PDMS)-based microfluidic device. To improve the wettability of hydrophilic continuous phase onto a hydrophobic PDMS microchannel, the surface was modified with 3-(trimethoxysilyl) propyl methacrylate (TPM) and then sequentially reacted with acrylic acid monomer solution, which produced selective covalent bonding between acrylic acids and methacrylate groups. For the proof of selective surface modification, tolonium chloride solution was used to identify the modified region and we confirmed that the approach was successfully performed. When water containing 0.5% w/w sodium dodecyl sulfate and 1% w/w Span80 with hexadecane were loaded into the selectively modified microfluidic channels, we can produce stable double emulsion. Based on the spreading coefficients, we predict the morphology of double emulsions. Our proposed method efficiently produces monodisperse double emulsions having 48.5 ${\mu}m$(CV:1.6%) core and 65.1 ${\mu}m$ (CV:1.6%) shell. Furthermore, the multiple emulsions having different numbers of core were easily prepared by simple control of flow rates.

• Korean Chemical Engineering Research
• /
• v.50 no.4
• /
• pp.733-737
• /
• 2012

This study reports the microfluidic preparation of monodisperse multiple emulsions using hydrodynamic control. To generate multiple emulsions, we fabricate a microfluidic capillary device based on co-flowing stream without any surface modification of microchannels. Based on the system, we can successfully generate multiple emulsions (W/O/W) using water containing 0.5 wt% Tween 20, n-hexadecane with 5 wt% Span 80, and 10 wt% poly (vinyl alcohol) (PVA) aqueous solution, respectively. Furthermore, we control the number of inner droplets by modulation of flow rate of inner fluid at fixed flow rate of middle and outer fluid. The multiple emulsions having precisely controlled inner droplets' size and number can be applicable for multiple chemical reactions as an isolated microreactor.

• Applied Chemistry for Engineering
• /
• v.34 no.2
• /
• pp.137-143
• /
• 2023

In this study, natural surfactants were extracted from Medicago sativa L. The O/W emulsification processes with the extracted natural surfactants were optimized using central composite design model-response surface methodology (CCD-RSM) and a 95% confidence interval was used to confirm the reasonableness of the optimization. Herein, independent parameters were the ratio of saponins to total surfactant (P), amount of surfactant (W), and emulsification speed (R), whereas the reaction parameters were the emulsion stability index (ESI), mean droplet size (MDS), and viscosity (V). Using the multiple reaction, the optimal conditions for the ratio of saponins to total surfactant, amount of surfactant, and emulsification speed for O/W emulsification were 49.5%, 9.1 wt%, and 6559.5 rpm, respectively. Under these optimal conditions, the expected values of ESI, MDS, and V as the reaction parameters were 89.9%, 1058.4 nm, and 1522.5 cP, respectively. The values of ESI, MDS, and V from these expected values were 88.7%, 1026.4 nm, and 1486.5 cP, respectively, and the average experimental error for validating the accuracy was about 2.3 (± 0.4)%. Therefore, it was possible to design an optimization process for evaluating the O/W emulsion process with Medicago sativa L. using CCD-RSM.

• Membrane Journal
• /
• v.27 no.6
• /
• pp.511-518
• /
• 2017

The membrane emulsification (ME) is a technology for producing emulsions with narrow size distribution by using the well-defined porous membranes such as the SPG membrane. In this study, the preparation of polycaprolactone (PCL) microcapsules by using the multiple emulsions obtained from membrane emulsification method is studied. After the making of $W_1/O$ single emulsions by sonication method, then $W_1/O/W_2$ multiple emulsions are formed by premix-ME method. The PCL microcapsules impregnated with BSA model drug are prepared by solvent evaporating from $W_1/O/W_2$ multiple emulsions. The effects of various parameters such as the ratio of disperse/continuous phase (D/C ratio), the concentration of PCL, emulsifier and model drug and the transmembrane pressure on the size and distribution of PCL microcapsules are investigated. The uniform PCL microcapsules with about $5{\sim}6{\mu}m$ of mean size and 26% of BSA loading are obtained by the premix membrane emulsification.

• Applied Chemistry for Engineering
• /
• v.8 no.4
• /
• pp.560-567
• /
• 1997

A new approach to obtain stable $W_1/O/W_2$ multiple emulsions has been studied ; The basis of the interfacial interaction between a PCL-PEO-PCL triblock copolymer and a lipophilic emulsifier in the dispersed oil phase was examined. $W_1/O/W_2$ multiple emulsions were prepared by the two-step method. Arlacel P-l35 was used as a liphophilic emulsifier and Synperonic PE/F 127 as a hydrophilic one. Eutanol-G was used as an oil phase. NaCl was encapsulated within the multiple emulsion droplets as the internal marker and its release rate studies were carried out. The suability of the multiple emulsions have been assessed by measuring Separation Ratios(%) and microscopic observations. The release of NaCl was significantly reduced in $W_1/O/W_2$ multiple emulsions containing PCL-PEO-PCL triblock copolymer(2k-4k-2k or 6k-4k-6k) in the oil phase. It may be concluded that the copolymer and the emulsifier form effective interfacial complex to enhance stability and to control the release rate. The effective diffusion coefficients of the NaCl were estimated as $2.64{\times}10^{-15}s$and $3.23{\times}10^{-16}gcm^2/s$ for the $W_1/O/W_2$ multiple emulsion containing 1.2 wt % of PCL-PEO-PCL triblock copolymers with compositions of 2k-4k-2k and 6k-4k-2k, respectively. The rate of release decreased with the increase of the initial concentration of NaCl. The results were examined in view of Higuchi mechanism. A kinetic model which is similar to the model for release of dispersed drugs from a polymeric matrix was found to be suitable for the release of NaCl from $W_1/O/W_2$ multiple emulsions.

• Korean Journal of Food Science and Technology
• /
• v.25 no.5
• /
• pp.475-480
• /
• 1993

This study was carried out to estimate the bind values of raw meats which are used as an input constaint in the least-cost formulation of an emulsion-type sausage. The least-cost formulation will be useful for Korean meat processore to produce more effectively as meat-grade system is put in force. The analysis results in compositions, functionalities, and pigment contents of raw meats were various according to the difference of species and their parts. The cohesiveness was correlated positively with moisture or protein content and negatively with fat content. Consequently two multiple regression equations for bind value could be derived from the compositions of raw meats. The equations then may be useful for predicting the bind value of a raw meat which presently has not been analysed.

• Proceedings of the SCSK Conference
• /
• 2003.09b
• /
• pp.307-307
• /
• 2003

Strategies to make finished products more stable and efficacious can take advantage of formulation technologies- ingredients and techniques - to improve their delivery into the skin by both enhanced penetration and delayed release. Nanometer range particles and emulsion droplets can be formed with a selection of either silicone copolyol or conventional organic surfactants and dispersion shear rates sufficient to generate stable submicron droplets. By incorporating these into systems with biomimetic liquid crystalline gel networks in either simple or multiple phase emulsions the skin delivery can be enhanced as shown in tape stripping experiments. Such systems can stabilize labile actives, such as Vitamin C and retinol, and aid delivery. Laboratories in U.S and Europe investigated actives including green tea polyphenols, salicylic acid and methyl and benzyl nicotinate.

• Applied Chemistry for Engineering
• /
• v.35 no.4
• /
• pp.316-320
• /
• 2024

To optimize the emulsion stability and antibacterial activity against Escherichia coli (E. coli) of cosmeceuticals using Scutellaria baicalensis extracts and olive wax as natural emulsifiers, we conducted a study. The independent variables were the amounts of Scutellaria baicalensis extracts and olive wax added. The response variables included the emulsion stability index (ESI) of the cosmeceuticals product and the inhibition diameter against E. coli. Through central composite design-response surface methodology (CCD-RSM), we obtained a statistically significant and reliable regression equation within a 95% confidence interval. By optimizing multiple responses, we determined that the optimal emulsification conditions that satisfied both ESI and E. coli inhibition diameter were 3.7 wt% of Scutellaria baicalensis extracts and 2.7 wt% of olive wax. The predicted ESI and E. coli inhibition diameter were 97.9% and 9.7 mm, respectively. When actual experiments were conducted under the optimal conditions, the measured ESI and E. coli inhibition diameter were 95.0% and 9.4 mm, respectively, with an average error rate of 3.2 ± 0.4%.

• Food Science and Biotechnology
• /
• v.18 no.5
• /
• pp.1161-1172
• /
• 2009

Food nanoemulsion systems consisting of water and oleoresin capsicum (OC), polyoxythylene sorbitan esters (Tween 20, 40, 60, and 80), propylene glycol (PG), sucrose monostearate (SM), and their corresponding mixtures were formulated to use as food vehicles. Tween 80 produced OC nanoemulsions with stable dispersions as one-phase systems, and the dertermined emulsification efficiencies clearly distinguished the ability of the various surfactants to emulsify OC. The nanoemulsions were prepared by both ultrasonication and self-assembly, and the nanoemulsion areas were determined using phase diagrams by measuring the sizes of the emulsions. One-phase nanoemulsions were presented, with a multiple cloudy region and phase separation that were dependent on the particle size of the emulsion. The OC nanoemulsions prepared by ultrasonication using systems of OC/Tween 80/water, OC/Tween 80/water+PG, and OC/Tween 80/water+SM, resulted in particle sizes ranging from 15 to 100 nm. Finally, the nanoemulsions maintained their initial sizes during storage, ranging from 65 to 92 nm.