Internal structure and pigment granules in colored alpaca fibers

Alpaca fibers have some distinct properties such as softness and warmth, which have not been fully understood in combination with the fiber internal structures. In the present investigation, the internal structures of alpaca fibers have been closely examined under the scanning electron microscope (SEM), especially in the longitudinal direction. The results showed that numerous pigment granules reside loosely inside pockets in brown and dark-brown alpaca fibers. These pigment granules were mainly distributed inside the cortical cells, the medullation regions as well as underneath the cuticles. Their size in the brown alpaca fibers was smaller and more uniformly round than in the dark-brown fibers. These granules in colored alpaca fibers loosen the bundle of cortical cells, providing many crannies in the fibers which may contribute to the superior flexibility, warmth and softness of the fibers. Moreover, there are no heavy metal elements found in the granules. The mordant hydrogen peroxide bleaching employed could eliminate the pigment granules and create many nano-volumes for further dyeing of fibers into more attractive colors.

Enhancing web-based adaptive learning with colored timed petri net

One of the issues for Web-based learning applications is to adaptively provide personalized instructions for different learning activities. This paper proposes a high level colored timed Petri Net based approach to providing some level of adaptation for different users and learning activities. Examples are given to demonstrate how to realize adaptive interfaces and personalization. Future directions are also discussed at the end of this paper.

Robust, electro-conductive, self-healing superamphiphobic fabric prepared by one-step vapour-phase polymerisation of poly(3,4-ethylenedioxythiophene) in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane and fluorinated alkyl silane

A robust, electrically conductive, superamphiphobic fabric was prepared by vapour-phase polymerisation of 3,4-ethylenedioxythiophene (EDOT) on fabric in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane (FD-POSS) and a fluorinated alkyl silane (FAS). The coated fabric had contact angles of 169° and 156° respectively to water and hexadecane, and a surface resistance in the range of 0.8–1.2 kΩ o⁻¹ . The incorporation of FD-POSS and FAS into the PEDOT layer showed a very small influence on the conductivity but improved the washing and abrasion stability considerably. The coated fabric can withstand at least 500 cycles of standard laundry and 10000 cycles of abrasion without apparently changing the superamphiphobicity, while the conductivity only had a small reduction after the washing and abrasion. More interestingly, the coating had a self-healing ability to auto-repair from chemical damages to restore the liquid repellency.

Investigating non-fluorinated anions for sodium battery electrolytes based on ionic liquids

In order for sodium batteries to become a safe, lower cost option for large scale energy storage, minimising the price of all components is important. We report here on the application of a pyrrolidinium room temperature ionic liquid comprising the dicyanamide anion as a successful electrolyte system for sodium metal batteries that does not contain expensive fluorinated species. The effects of plating/stripping of sodium from Na metal electrodes has been investigated in a symmetrical Na | electrolyte | Na configuration at a current density of 10 μA cm− 2. Comparisons are drawn to reference organic electrolytes comprising propylene carbonate-fluoroethylene carbonate. Residual water molecules in the ionic liquid electrolyte are observed to have a significant effect upon the surface film and subsequent favourable plating/stripping behaviour of symmetrical cells and this is explored in detail. An increase of the moisture content from 90 ppm to 400 ppm impedes both electrodeposition and electrodissolution of the Na+/Na. This is investigated at Ni electrodes using cyclic voltammetry at different Na+-salt concentrations to further understand the mechanism.

A novel route for the preparation of dimeric tetraorganodistannoxanes

The reaction of polymeric diorganotin oxides, (R₂SnO)_n (R=Me, Et, n-Bu, n-Oct, c-Hex, i-Pr, Ph), with saturated aqueous NH₄X (X=F, Cl, Br, I, OAc) in refluxing 1,4-dioxane afforded in high yields dimeric tetraorganodistannoxanes, [R₂(X)SnOSn(X)R₂]₂, and in a few cases diorganotin dihalides or diacetates, R₂SnX₂. The reported method appears suitable for the synthesis of fluorinated tetraorganodistannoxanes. Identification of [R₂(OH)SnOSn(X)R₂]₂ (R=n-Bu; X=Cl, Br) and [R₂(OH)SnOSn(X)R₂] [R₂(X)SnOSn(X)R₂] suggest a serial substitution mechanism starting from [R₂(OH)SnOSn(OH)R₂]₂. X-ray crystal structure determinations are reported for [Me₂(AcO)SnOSn(OAc)Me₂]₂ (29a), [i-Pr₂(Br)SnOSn(Br)i-Pr₂]₂ (20a), [c-Hex2(F)SnOSn(F)c-Hex₂]₂ (5a) and [c-Hex₂(F)SnOSn(Cl)c-Hex₂]₂ (36), respectively. These show the presence of a central (R₂Sn)₂O₂ core that is connected, via the oxygen atoms, to R₂Sn entities. Acetate (29a) or halides (5a, 20a, 36) complete the coordination about the tin centres.

A new second-order method for blind signal separation from dynamic mixtures

This paper presents a new approach to separate colored stationary signals mixed by convolutive channels. A cost function is proposed by employing linear constraint to the demixing vectors. The linear constraint is shown to be sufficient for avoiding trivial solution. The minimization of the cost function is performed using the Lagrangian method. Simulation results demonstrate the performance of the algorithm.

Chemiluminescence from the Sakaguchi reaction

The Sakaguchi reaction between arginine and hypohalites in the presence of α-phenols (Fig. 1) has been extensively employed for the colorimetric determination of this amino acid [1] M.A Parniak, G Lange and T Viswanatha, Quantitative determination of monosubstituted guanidines: a comparative study of different procedures, J. Biochem. Biophys. Methods 7 (1983), pp. 267–276. Abstract | View Record in Scopus | Cited By in Scopus (8)[1] and [2]. There have been a number of modifications to the reaction for the determination of arginine to improve the color stability and sensitivity. The Sakaguchi reaction is much faster with hypobromite than with hypochlorite, but the colored product fades at a higher rate; however, this can be prevented by adding urea to remove the excess hypobromite [3]. Although 1-naphthol was originally used as the chromogen, other phenols including 2,4-dichloro-1-naphthol [4], 8-quinolinol [5], 5-chloro-7-iodo-8-quinolinol [6], and thymol [2] (Fig. 1) have provided superior analytical figures of merit. We have found that the reaction between arginine and hypobromite is chemiluminescent [7], which has been used to develop an analytical procedure that is rapid, simple, and selective for arginine in the presence of other amino acids.

Ian's story : the complex interaction of ethnicity, class and masculinities

In this paper, a narrative is used to convey the complex connectedness that exists between class, ethnicity and masculinity. The story is of Ian, a successful academic who describes himself as Eurasian, and traces his development through parts of his childhood and into his professional career, using what Gough (1994) describes as a 'realistic fiction'. Relevant literature on masculinities and ethnicity is considered. There is some evidence to suggest that Ian has developed a fluid version of masculinity as a result of his Asian-Australian upbringing, and that he expresses different masculinities according to the social settings in which he finds himself. The paper concludes, just as Ian's story does, that masculinity interacts with class and ethnicity. This accords with Connell's (1995) caution that it is dangerous to think that there is a colored masculinity or a working class masculinity, and that the milieux of class and race need to be considered as well.

A new second order method for blind signal separation from convolutive mixtures

This paper presents a new approach to separate colored signals mixed by FIR (finite impulse response) and MIMO (multiple-input multiple-output) channels. A cost function is proposed by employing linear constrainit to the de mixing vectors. The linear constraint is shown to be sufficient for avoiding trivial solution. The minimization of the cost function is performed using the Lagrangian method. Simulation results demonstrate the performance of the algorithm.

Blind identification of FIR MIMO channels by decorrelating subchannels

We study blind identification and equalization of finite impulse response (FIR) and multi-input and multi-output (MIMO) channels driven by colored signals. We first show a sufficient condition for an FIR MIMO channel to be identifiable up to a scaling and permutation using the second-order statistics of the channel output. This condition is that the channel matrix is irreducible (but not necessarily column-reduced), and the input signals are mutually uncorrelated and of distinct power spectra. We also show that this condition is necessary in the sense that no single part of the condition can be further weakened without another part being strengthened. While the above condition is a strong result that sets a fundamental limit of blind identification, there does not yet exist a working algorithm under that condition. In the second part of this paper, we show that a method called blind identification via decorrelating subchannels (BIDS) can uniquely identify an FIR MIMO channel if a) the channel matrix is nonsingular (almost everywhere) and column-wise coprime and b) the input signals are mutually uncorrelated and of sufficiently diverse power spectra. The BIDS method requires a weaker condition on the channel matrix than that required by most existing methods for the same problem.