Surfactant

Chocolate beverage powders (CBPs) were produced from alkalized cocoa powder (ACP) at 10–30% and soy lecithin (SL) at 0–4%. Response surface methodology (RSM) was used to determine the optimum level of ACP and SL on sedimentation, wettability, bulk density, despersibility, moisture content and flavor acceptability. SL was effective on wettability, and it also showed an optimum level for sedimentation and bulk density, while ACP was found to be significant for all physical properties. For sensory evaluation, flavor was acceptable at 20% ACP level soy taste was detected by panelists in CBPs with high SL and low ACP contents. It was found that as the ACP content was increased the soy taste of CBPs decreased. For overall physical characteristics, the optimum levels of 20% of ACP and 2–4% of SL were selected.

Context: Glutathione in the reduced form (GSH) is the predominant intracellular form, which acts as a strong antioxidant. However, it has low skin permeability due to the high hydrophilicity. Hence, the objective of this study was to prepare GSH by using microspheres delivery system and adding surfactant to overcome the barrier function of the skin.

Aims: To investigate the effect of polymer and surfactant on the characteristics and release profile of GSH–alginate microspheres.

Methods: GSH-alginate microspheres were prepared using ionotropic gelation method by aerosolisation. A randomized full factorial design was applied to prepare four different formulations of glutathione loaded alginate microspheres. Design was applied for all formulations to study about effect of independent variables of polymer and crosslinker on the entrapment efficiency (EE), drug loading (DL), particle size, yield, and in vitro drug release profile. For release study, microspheres formulas were also compared to microspheres, which applied into gel base.

Results: The GSH-alginate microspheres had a high EE ranging from 34.74 ± 0.07% to 56.63 ± 0.36%, with small particle sizes ranging from 1.89 ± 0.03 µm to 2.42 ± 0.08 µm, and drug loading ranging from 5.72 ± 0.05% to 6.23 ± 0.02%. The kinetic analysis of all release profiles was found to follow Higuchi’s diffusion model. EE, DL, particle size, and yield variables had a significant effect on the dependent variables (p<0.05), and flux had no significant effect on the dependent variables (p>0.05).

Conclusions: All formulas produced high yield and encapsulation efficiency and small size particles. From the 22 randomized full factorial design, there was showed that the combination of the use of surfactant and polymer concentration significantly affected DL and EE.

Physico-chemical investigation on adsorption of congo red, an anionic azo dye by chitosan hydrobeads has been carried out. Adsorption process has been found to be dependant on temperature with optimum activity at 30 °C. Both ionic interaction as well as physical forces is responsible for binding of congo red with chitosan. Theoretical correlation of the experimental equilibrium adsorption data for congo red–chitosan hydrobeads system would be best explained by linearized form of Langmuir isotherm model. The kinetic results follow pseudo second-order rate equation. pH of the experimental solution influenced congo red adsorption inversely, and ∼20.0% of the dye could be desorbed from the loaded beads by changing the pH of the solution to alkaline range (∼pH 12.0). Both sodium chloride and sodium dodecyl sulfate significantly influenced the adsorption process.

A series of experiments were performed to further investigate the phenomenon of shear-banding in surfactant solutions. Many surfactant solutions, through their unique amphiphilic chemistry, form long wormlike micelle structures which behave like living polymers. These wormlike micelles have interesting viscoelastic properties and have been the subject of a number of recent studies. These water-based surfactant systems are widely used in

In this paper, an experimental investigation, an analytical analysis and a numerical model of a typical four-point bending test on a honeycomb sandwich panel are proposed. The honeycomb core is modelled as a single solid layer of equivalent material properties. Analytical and numerical (finite element) homogenization approaches are used to compute the effective properties of the honeycomb core. A general kinematic model (unified formulation) has been adopted and used for the modelling of honeycomb sandwich panel submitted to the bending test. A comparative study of major classes of representative theories has been considered. Qualitative and quantitative assessments of displacement, stress have been presented and discussed.

The present study examines the influence of different contents and types of process control agent (PCA), i.e., stearic acid (SA) and ethylene-bis-stearamide (EBS), on the microstructural evolution and characteristics of Ti-16Sn-4Nb (wt pct) alloy powders and bulk samples. The characterization of the powders and bulk samples was carried out by using chemical analysis, optical microscopy, scanning electron microscopy (SEM) combined with energy-dispersive spectrometry (EDS), and X-ray diffractometry. Results indicated that the powder recovered from the ball milling containers increased with increasing amounts of SA and EBS. Furthermore, adding more SA or EBS to the powder mixture resulted in a considerably smaller particle size, with a flaky-shaped morphology for the given ball milling time. Also, a slightly higher effectiveness was found for EBS when compared to SA. Meanwhile, the addition of both SA and EBS led to a delay in the alloy formation during mechanical alloying (MA) and caused contamination of the material with mainly carbon (C) and oxygen (O). An optimum amount of 1 wt pct PCA led to a good balance between cold welding and fracturing, and thus favored the formation of the titanium alloy. The microstructural observation of the bulk alloy showed a homogeneous distribution of fine Nb-rich β-phase colonies within the α-Ti matrix with the addition of PCA less than 1 wt pct.

The key step in the preparation of mesoporous silica materials is the removal of organic templates occluded inside the pores including nonionic, cationic, anionic surfactants and even ionic liquid (IL). The most common method to remove templates is conventional calcination under air at 550°C. Although templates can be completely removed from the pores, calcination suffers many serious drawbacks including significant framework shrinkage, the collapse of the ordered structure, reduction of silanol concentrations on the pore wall (which are of high importance for postmodification), generation of large amounts of CO 2 and organic amine compounds, the presence of carbon deposits or coke as a contaminant, elimination of organic functionalities (such as organoalkoxysilanes with amino groups), and the inability to recover or reuse expensive organic templates. That is why many attempts have been reported in the literature to develop novel methods for removing organic templates that are favorable from both economic and environmental standpoints for potentially large-scale applications. The current study reviews the recent development methods for template removal from various types of mesoporous silica materials. We have divided the template removal approaches into two categories: physical method and chemical method. The effects of those methods are discussed in detail on the textural and structural properties of mesoporous silica materials along with the template removal mechanism and their pores and coins.