• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.141-145
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• 2004

This study was pursued to measure skin feeling of cosmetics by mechanical methods. For this attempt, skin feeling of cosmetics such as spreading properties, tackiness, and residual greasy feeling after skin application was explored with the amount and kinds of cosmetic compositions-emulsifiers, waxes, thickeners, polyols, and oils. Furthermore, the relationship between these cosmetic compositions and viscometry of cosmetic products was studied. In case of emulsifiers, waxes, and thickeners, they showed strong correlation with both skin feeling and the value of phase angle, the property of viscometry, respectively, while polyols and oils were observed a special tendency neither skin feeling nor the property of viscometry. It leads to the conclusion that skin feeling may be corresponded to not values of a mechanical measure completely but a function of several properties. We expect that a better correlation can be discovered with additionally measured properties such as friction, volatility, etc.

• Computers and Concrete
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• v.15 no.4
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• pp.687-707
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• 2015

A finite element computer code for short-term analysis of steel-concrete composite structures is extended to study long-term effects under service loads, in the present work. Long-term effects are important in engineering design because they influence stress and strain distribution of the structural system and therefore contribute to the increment of deflections in these structures. For creep analysis, a rheological model based on a Kelvin chain, with elements placed in series, was employed. The parameters of the Kelvin chain were obtained using Dirichlet series. Creep and shrinkage models, proposed by the CEB FIP 90, were used. The shear-lag phenomenon that takes place at the concrete slab is usually neglected or not properly taken into account in the formulation of beam-column finite elements. Therefore, in this work, a three-dimensional numerical model based on the assemblage of shell finite elements for representing the steel beam and the concrete slab is used. Stud shear connectors are represented for special beam-column elements to simulate the partial interaction at the slab-beam interface. The two-dimensional representation of the concrete slab permits to capture the non-uniform shear stress distribution in the horizontal plane of the slab due to shear-lag phenomenon. The model is validated with experimental results of two full-scale continuous composite beams previously studied by other authors. Results are given in terms of displacements, bending moments and cracking patterns in order to shown the influence of long-term effects in the structural response and also the potentiality of the present numerical code.

• Polymer(Korea)
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• v.35 no.6
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• pp.574-579
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• 2011

3-Roll coating process as a key application technology for manufacturing automotive pre-painted metal-sheets has been studied. The 3-Roll coating system for this study consists of pick-up roll for picking up and distributing coating liquid from the reservoir, metering roll to properly meter coating liquid in metering gap regime, and applicator roll for directly transferring liquid into metal-sheet surface. Flow dynamics and operable coating windows of a polymeric paint (primer) with shear-thinning rheological property have been correlated with processing parameters such as speed ratio and metering gap between pick-up and metering rolls. In the uniform coating regime, dry coating thickness increased with increasing metering gap or decreasing speed ratio. Ribbing and cascade instabilities were observed in low speed and high speed ratio conditions, respectively. It is revealed that lower speed ratio makes severity and wavelength of the ribbing increase, aggravating flow instability in coating systems.

• Advances in concrete construction
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• v.8 no.1
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• pp.65-76
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• 2019

This paper investigates the effect of recycled glass powder (RGP) on flowing properties of self-compacting mortars (SCMs) containing different ratios of fillers and superplasticizer dosages. Fly ash (FA), nano-silica (NS), micro-silica (MS), metakaolin (MK) and rice husk ash (RHA) are used as fillers and their synergistic effect with RFP is studied. The effects of fillers and high-range water reducer (HRWR) on flowing ability of mortars are primarily determined by slump flow and V-funnel flow time tests. The results showed that for composites with a higher RGP content, the mortar flowing ability increased but tended to decrease when the composites containing 10% MK or 5% RHA. However, the flowing ability of samples incorporating 5% RGP and 10% SF or 25% FA showed an opposite result that their slump flow spread decreased and then increased with increasing RGP content. For specimens with 3% NS, the influence of RGP content on flowing properties was not significant. Except RHA and MS, the fillers studied in this paper could reduce the dosage of HRWR required for achieving the same followability. Also, the mixture parameters were determined and indicated that the flowability of mixtures was also affected by the content of sand and specific surface area of cement materials. It is believed that excess fine particles provided ball-bearing effect, which could facilitate the movement of coarse particles and alleviate the interlocking action among particles. Also, it can be concluded that using fillers in conjunction with RGP as cementitious materials can reduce the material costs of SCM significantly.

• Geomechanics and Engineering
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• v.36 no.1
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• pp.39-50
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• 2024

Bitumen and high-quality subangular aggregates, the two principal materials used for asphalt concrete construction, are finite and expensive materials. The general availability of crumb rubber and naturally occurring aggregates of different shapes, especially flat and elongated shapes, indicates that they are feasible alternative materials for expanding the volume of bitumen and utilizing a wider range of aggregate shapes for the development of asphalt concrete, with an associated environmental benefit. The study investigated the effect of adding up to 15% crumb rubber and aggregates sorted into different groups, i.e., rounded, elongated, flat, and their combinations, on the rheological and mechanical properties and durability of 50/70 of hot-mix asphalt pavement. The addition of crumb rubber decreased ductility and penetration but increased the softening point. For a 5.5% bitumen content, asphalt concrete briquettes consisting of 7% crumb rubber and three types of aggregate shapes, i.e., 100% rounded, a mix of 75% rounded and 25% elongated, and a mix of 75% rounded, 15% elongated and 10% flat, were associated with high Marshall stability and indirect tensile strength as well as low lateral deformation due to their high solidity and moderate angularity ratio. Also, the addition of 7% crumb rubber resulted in a significant improvement in the tensile strength ratio and rebound strain of briquettes consisting of 75% rounded and 25% elongated aggregates and those with 75% rounded, 15% elongated and 10% flat aggregates. In relation to the parameters investigated, the three groups of briquettes met some of the local (South Africa) requirements for the surface course and base course of low traffic volume roads.

• Korea-Australia Rheology Journal
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• v.17 no.3
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• pp.131-140
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• 2005

In this work we show the results of our most recent Direct Numerical Simulations (DNS) of turbulent viscoelastic channel flow using spectral spatial approximations and a stabilizing artificial diffusion in the viscoelastic constitutive model. The Finite-Elasticity Non-Linear Elastic Dumbbell model with the Peterlin approximation (FENE-P) is used to represent the effect of polymer molecules in solution, The corresponding rheological parameters are chosen so that to get closer to the conditions corresponding to maximum drag reduction: A high extensibility parameter (60) and a moderate solvent viscosity ratio (0.8) are used with two different friction Weissenberg numbers (50 and 100). We then first find that the corresponding achieved drag reduction, in the range of friction Reynolds numbers used in this work (180-590), is insensitive to the Reynolds number (in accordance to previous work). The obtained drag reduction is at the level of $49\%\;and\;63\%$, for the friction Weissenberg numbers 50 and 100, respectively. The largest value is substantially higher than any of our previous simulations, performed at more moderate levels of viscoelasticity (i.e. higher viscosity ratio and smaller extensibility parameter values). Therefore, the maximum extensional viscosity exhibited by the modeled system and the friction Weissenberg number can still be considered as the dominant factors determining the levels of drag reduction. These can reach high values, even for of dilute polymer solution (the system modeled by the FENE-P model), provided the flow viscoelasticity is high, corresponding to a high polymer molecular weight (which translates to a high extensibility parameter) and a high friction Weissenberg number. Based on that and the changes observed in the turbulent structure and in the most prevalent statistics, as presented in this work, we can still rationalize for an increasing extensional resistance-based drag reduction mechanism as the most prevalent mechanism for drag reduction, the same one evidenced in our previous work: As the polymer elasticity increases, so does the resistance offered to extensional deformation. That, in turn, changes the structure of the most energy-containing turbulent eddies (they become wider, more well correlated, and weaker in intensity) so that they become less efficient in transferring momentum, thus leading to drag reduction. Such a continuum, rheology-based, mechanism has first been proposed in the early 70s independently by Metzner and Lamley and is to be contrasted against any molecularly based explanations.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.871-878
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• 2004

Pulsed electric fields(PEF) technology is one of the latest nonthermal methods of food processing for obtaining safe and minimally processed foods. This technology can be effectively explored for obtaining safe food with minimum effect on nutritional, flavor, rheological and sensory qualities of food products. The process involves the application of high voltage(typically 20 ${\sim}$ 80 kv/cm) to foods placed between two electrodes. The mode of inactivation of microorganism; by PEP processing has been postulated in term; of electric breakdown and electroporation. The extent of destruction of microorganisms in PEF processing depends mainly on the electric field strength of the pulses and treatment time. For each cell types, a specific critical electric field strength and specific critical treatment time are required depending on the cell characteristics and the type and strength of the medium where they have been present. The effect also depends on the types of microorganisms and their phase of growth. A careful combination of processing parameters has to be selected for effective processing. The potential applications of PEF technology are numerous ranging from biotechnology to food preservation. With respect to food processing, it has already been established that, the technology is non-thermal in nature, economical and energy efficient, besides providing minimally processed foods. This article gives a brief overview of this technology for food processing applications.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.927-935
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• 2005

The objectives of this study were to investigate the soaking properties of the high-dietary fiber rice 'Goami 2'and to develop korean white Gruel prepared with Goami 2. With increasing soaking time at room temperature ($20^{\circ}C$), the water absorbing character of Goami 2 and Ilpum significantly increased during the first hour of soaking time, after which it remained constant. On the contrary, the hardness of Goami 2 and Ilpum significantly decreased with increasing soaking time until one hour, after which it remained constant. The properties of Korean white gruel were evaluated using two varieties of rice (Goami 2, Ilpum) and three blending times (10, 20 and 30 seconds respectively). The rice flour of Goami 2 for Korean white gruel showed a greater number of small particles (<20 $\mu$m) than that of Ilpum. Hunter a'and b'values of Korean white gruel prepared with Goami 2 were higher than that of Korean white gruel prepared with Ilpum. The consistency values on Bostwick consistometer of Korean white gruel prepared with Goami 2 were higher than those of Korean white gruel prepared with Ilpum. The texture of Korean white gruel was examined using a back extrusion rig. All of the rheological parameters of Korean white gruel prepared with Goami 2 were decreased with increasing blending time, while in llpum they were increased. In the sensory evaluation results, the overall acceptability of korean white gruel prepared with Goami 2 blended for 20sec showed the highest sensory scores and desirability.