The excellent water-solubility of N-[3-(dimethyl-amino)propyl] docosanamide chloride : the most eco-friendly cationic hair conditioning agent

A new hair-conditioning agent, N-[3-(dimethylamino)propyl]docosanamide (APA-22) hydrochloric acid salt (APA-22 HCl), has excellent solubility in water with a solubility limit over 10-times larger than that of other APA hydrochloric salts with shorter alkyl chain lengths. The physicochemical characteristics of APA-22 HCl were studied at 25 degrees C by using equilibrium surface tension (gamma), solubilization of an oil-soluble dye, steady-state fluorescence, and chloride ion selective electrode techniques. The APA-22 HCl salt is considered to form an aggregate at a concentration, C(1), which is about twice the concentration of the solubility limit of APAs with shorter alkyl chains. At a higher concentration, C(2), the aggregates of APA-22 HCl start forming another kind of aggregate, which is able to solubilize oil-soluble materials. That is, C(1) is considered to represent the critical aggregation concentration (cac) and C(2) a morphology transition. In the concentration region between C(1) and C(2) the solutions are seemingly transparent whereas at above C(2) they appear bluish or translucent. Since the Krafft point of APA-22 HCl is 55 degrees C, all the solutions, including the aggregates, are thought to exist in metastable states. Notably, however, these metastable solutions do not change significantly over a few months. The excellent solubility of APA-22 HCl in water is considered to be a result of this unique stepwise aggregation with increasing concentration.     

Energy Transfer Enables 1.53 μm Photoluminescence from Erbium-Doped TiO2 Semiconductor Nanocrystals Synthesized by Ar/O2 Radio-Frequency Thermal Plasma

Highly crystalline, highly luminescent nanopowders of Er³⁺-doped TiO₂ have been successfully synthesized via one-step Ar/O₂ radio-frequency thermal plasma processing. Energy transfer from the TiO₂ host to Er³⁺ activators has been confirmed by combined means of UV-vis, excitation, and photoluminescence spectroscopies. As a consequence, bright photoluminescence at ∼1.53 μm was observed from the nanopowders either by directly exciting the Er³⁺ activator or by exciting the TiO₂ host lattice. A comparative study shows that the nanopowder of the same system made via coprecipitation lacks the energy transfer. The plasma-generated nanopowders may thus find applications in optoelectronic devices.     

Calculation of effective delayed neutron fraction with Monte Carlo perturbation techniques

New methods are proposed to estimate the effective delayed neutron fraction β_eff in Monte Carlo calculations: the eigenvalue methods jointly used with the differential operator sampling and correlated sampling techniques. In particular, the eigenvalue method with the differential operator sampling technique has a distinct feature that it theoretically gives an exact β_eff value. To verify the proposed methods, Monte Carlo calculations are performed for several systems with simple geometry. It is found that the results obtained with the proposed methods agree with the reference deterministic results within sufficiently small statistical uncertainties. The indirect perturbed source effect must be taken into account to estimate an exact β_eff value.     

Structure and physical properties of dried Tetra-PEG gel

We investigated crystal structure, and thermal, swelling, and deformation behaviors of dried tetrafunctional (polyethylene glycol) gel, Tetra-PEG gel, with narrow molecular distribution. Tetra-PEG gel consists of two kinds of symmetrical tetrahedron-like PEG macromonomers with a fixed molecular weight. In spite of network structure with rather small molecular weight between cross-links (M_c) (≈5000), the dried Tetra-PEG gels were found to be capable of crystallization. The crystalline melting temperature (T_m) and the degree of crystallinity (X_c) of dried Tetra-PEG gels obtained by differential scanning calorimetry (DSC) were substantially constant against the polymer volume fraction at preparation (?₀). Furthermore, the corrected elastic modulus (G) of dried Tetra-PEG gels did not depend on ?₀. These experimental results indicate that the there exist negligible entanglements in the dried Tetra-PEG network irrespective of ?₀. In other words, Tetra-PEG gels do not have significant topological inhomogeneities.     

Properties of disturbance waves in vertical annular two-phase flow

Disturbance waves play an important role in interfacial transfer of mass, momentum and energy in annular two-phase flow. In spite of their importance, majority of the experimental data available in literature on disturbance wave properties such as velocity, frequency, wavelength and amplitude are limited to near atmospheric conditions (Azzopardi, B.J., 1997. Drops in annular two-phase flow. International Journal of Multiphase Flow, 23, 1-53). In view of this, air-water annular flow experiments have been conducted at three pressure conditions (1.2, 4.0 and 5.8 bar) in a tubular test section having an inside diameter 9.4 mm. At each pressure condition liquid and gas phase flow rates are varied over a large range so that the effects of density ratio, liquid flow rate and gas flow rate on disturbance wave properties can be studied systematically. A liquid film thickness is measured by two flush mounted ring shaped conductance probes located 38.1 mm apart. Disturbance wave velocity, frequency, amplitude and wavelength are estimated from the liquid film thickness measurements by following the statistical analysis methods. Parametric trends in variations of disturbance wave properties are analyzed using the non-dimensional numbers; liquid phase Reynolds number (Re_f), gas phase Reynolds number (Re_g), Weber number (We) and Strouhal number (Sr). Finally, the existing correlations available for the prediction of disturbance wave velocity and frequency are analyzed and a new, improved correlation is proposed for the prediction of disturbance wave frequency. The new correlation satisfactorily predicted the current data and the data available in literature.     

Numerical analysis of a reactive extrusion process. Part II: Simulations and verifications for the twin screw extrusion

A newly designed extruder reactor for grafting vinyl monomers onto polyolefins was studied experimentally and theoretically. The process was made up of a self‐wiping co‐rotating twin screw extruder with a separated reaction zone and two vent zones. The reactive extrusion was performed using a linear low density polyethylene, vinyltrimethoxysilane and di‐t‐butylperoxide under different operation conditions. For the purpose of process analysis, we built a computer simulation based on the reaction kinetics and rheological models studied in the preceding paper. The flow field in the extruder was calculated by the flow analysis network (FAN) method with non‐isothermal non‐Newtonian flow conditions. The iterative procedure was organized to predict local pressure, filling factor, cumulative residence time and temperature along the extruder. Furthermore, we succeeded in representing the profiles of reaction conversion and shear viscosity. Calculated results showed good agreements with the experimental data.     

α,ω-二元羧酸单酯在铑系双组份催化剂上加氢制ω-羟基羧酸酯

在小型高压反应釜中研究了铑系催化剂对于α,ω－ 二元羧酸单酯加氢生成ω－ 羟基羧酸酯的催化性能。结果表明,Ｒｈ － Ｒｅ 以及Ｒｈ － Ｍｏ 双组份催化剂具有良好的催化加氢性能;α,ω－ 十五烷二酸单甲酯在Ｒｈ － Ｒｅ 和Ｒｈ － Ｍｏ双组份催化剂上加氢生成ω－ 羟基十五烷酸甲酯的收率分别达到８７－５ ％ 和８４－７ ％ ;其它α,ω－ 二元羧酸单酯在Ｒｈ －Ｍｏ 双组份催化剂上加氢生成相应的ω－ 羟基羧酸酯的收率也达到８０－９ ％ ～９１－３ ％ 。反应温度对α,ω－ 二元羧酸单酯加氢生成ω－ 羟基羧酸酯的收率有较大的影响,乙二醇二甲醚作为溶剂有利于目的产物的生成。     

Reaction and Formation of Crystalline Silicon Oxynitride in Si–O–N Systems under Solid High Pressure

Oxidized amorphous Si₃N₄ and SiO₂ powders were pressed alone or as a mixture under high pressure (1.0–5.0 GPa) at high temperatures (800–1700°C). Formation of crystalline silicon oxynitride (Si₂ON₂) was observed from amorphous silicon nitride (Si₃N₄) powders containing 5.8 wt% oxygen at 1.0 GPa and 1400°C. The Si₂ON₂ coexisted with β-Si₃N₄ with a weight fraction of 40 wt%, suggesting that all oxygen in the powders participated in the reaction to form Si₂ON₂. Pressing a mixture of amorphous Si₃N₄ of lower oxygen (1.5 wt%) and SiO₂ under 1.0–5.0 GPa between 1000° and 1350°C did not give Si₂ON₂ phase, but yielded a mixture of α,β-Si₃N₄, quartz, and coesite (a high-pressure form of SiO₂). The formation of Si₂ON₂ from oxidized amorphous Si₃N₄ seemed to be assisted by formation of a Si–O–N melt in the system that was enhanced under the high pressure.     

Modulation of visual attention assessed using the Stroop task during the menstrual cycle: Comparison between the menstrual and ovulation phases

Women might have changes in perception and cognition of colours according to hormonal changes during the menstrual cycle. Colours are often associated with specific emotional facial expressions, but how these two factors interact with each other and differ according to the cycle has remained unclear. We investigated attentional interference between colours and emotional facial expressions for women in the menstrual compared to the ovulation phases by colour judgment based on the Stroop tasks. Participants identified the colours (either red, yellow, or blue) of three types of face stimuli (happy, neutral, or sad) and corresponding scrambled face stimuli by pressing buttons, and we recorded participants' reaction times. The results showed better performance in the menstrual phase than in the ovulation phase. An interference effect was not observed. However, in the scrambled face stimuli task, only the reaction time for happy scrambled face shape and red did not differ between the phases. Thus, participants might pay stronger attention to faces with colours in the menstrual phase than in the ovulation phase but weaker attention to scrambled face shapes in the menstrual phase.     

Influence of pulsed electric field on enzymes,bacteria and volatile flavor compounds of unpasteurized sake

A pulsed electric field(PEF) was applied to unpasteurized sake at constant temperatures, at which α-amylase was not inactivated. We adjusted the input energy to be identical for the temperatures by changing the number of PEF application, because the current significantly increased with the temperature, even the amplitude of the applied voltage was identical. As a result, the α-amylase was seemed to be inactivated by PEF application, not due to thermal effect.The glucoamylase was significantly inactivated by PEF. Moreover, the acid carboxypeptidase was inactivated by PEF at 4 °C but significantly activated at 25 °C. These results show that the sensitivity of enzyme to PEF application differs depending on the types of enzyme and treatment temperature. On the other hand, the colony number of bacteria was remarkably decreased, but the amount of the volatile flavor compounds was not decreased by PEF application.