Comparative analysis of two selective bleaching methods on alpaca fibers

Dark brown Alpaca fiber was reduced in shade via selective bleaching with peroxide. Two selective oxidative bleaching methods were tested on alpaca top to assess their effectiveness for color removal and fiber quality properties. Color change, bundle strength, weight loss, fiber diameter, surface modification, dye-ability and dye wash fastness were assessed for both methods and compared with the original brown top. Bleach method 1 (BL-I) showed little surface modification, 5.8 % weight loss and 2.4 % strength loss. D1925 yellowness index was reduced to 74.3 from 83.1 and provided a good base for the dyeing of medium to deep shades. Bleach method 2 (BL-II) displayed considerable surface modification, 7.8 % weight loss and 18 % strength loss. BL-II also resulted in a mean diameter reduction of 1.9 micron during bleaching. Yellow-ness was reduced to 64.5 from 83.1 and provided a very good base for the dyeing of medium to deep shades. BL-I showed better exhaustion of the pre-metallised dye Lanaset Violet B than BL-II. Wash fastness for BL-II was 1 grey scale unit poorer than BL-I. BL-II showed far better color clarity at pale depths however the wash fastness of the finished product was not good enough to maintain the depth or clarity of the color. BL-I showed poorer clarity of color but exhibited better wash fastness results.

Modeling the tensile behavior of fiber bundles with irregular constituent fibers

In this paper, the effect of fiber dimensional irregularities on the tensile behavior of fiber bundles is modeled, using the finite element method (FEM). Fiber dimensional irregularities are simulated with sine waves of different magnitude. The specific stress-strain curves of fiber bundles and the constituent single fibers are obtained and compared. The results indicate that fiber diameter irregularity along fiber length has a significant effect on the tensile behavior of the fiber bundle. For a bundle of uniform fibers of different diameters, all constituent fibers will break simultaneously regardless of the fiber diameter. Similarly, if fibers within a bundle have the same pattern and level of diameter irregularity along fiber length, the fibers will break at the same time also regardless of the difference in average diameter of each fiber. In these cases, the specific stress and strain curve for the bundle overlaps with that of the constituent fibers. When the fiber bundle consists of single fibers with different levels of diameter irregularity, the specific stress-strain and load-elongation curves of the fiber bundle exhibit a stepped or “ladder” shape. The fiber with the highest irregularity breaks first, even when the thinnest section of the fiber is still coarser than the diameter of a very thin but uniform fiber in the bundle. This study suggests that fiber diameter irregularity along fiber length is a more important factor than the fiber diameter itself in determining the tensile behavior of a fiber bundle consisting of irregular fibers.

Evaluating the softness of animal fibers

Softness is an important property of textile fibers, and animal fibers in particular. At present, there is no reliable method for objectively evaluating fiber softness. This paper examines a simple technique of such evaluations by pulling a bundle of parallel fibers through a series of pins. Softer fibers with lower bending rigidities and smoother surfaces should have lower pulling forces. Alpaca and wool fibers are used in this study to validate this technique, and the results suggest that pulling force measurements can reflect differences in fiber softness.

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.

Implementation of novel methods of global and nonsmooth optimization : GANSO programming library

We discuss the implementation of a number of modern methods of global and nonsmooth continuous optimization, based on the ideas of Rubinov, in a programming library GANSO. GANSO implements the derivative-free bundle method, the extended cutting angle method, dynamical system-based optimization and their various combinations and heuristics. We outline the main ideas behind each method, and report on the interfacing with Matlab and Maple packages.

The softness of alpaca fibres

Softness is a unique selling point for luxury fibres such as alpaca. However, there is very little objective data on the softness of animal fibres. This study first establishes that the resistance to compression (RtC) behaviour of alpaca and wool fibres is quite different, and that the RtC method can not be used to examine the softness of different animal fibres. It then reports a new method for evaluating fibre softness. This method is based on the measurement of the force required to pull a fibre bundle through a series of parallel pins. This force, reflecting the combined effect of fibre surface properties, fibre diameter and rigidity, can achieve reasonable discrimination between fibres of varying levels of softness, such as alpaca and wool. Mechanisms responsible for the superior softness of alpaca fibres are discussed also.

Extensive, economical and elegant : the habitus of gentility in early nineteenth century Sydney

This paper challenges the modern expectation that mahogany furniture and silver cutlery were self-evident indicators of gentry status in colonial Sydney through close analysis of a bundle of middle class household inventories of the 1840s. They are considered as evidence of habitus--the structuring interaction of mentality with the material world--in order to demonstrate the active principle of consumption in the claim or assertion of bourgeois standing, which was particularly lively in the colony. A range of competences can he seen in the practice of gentility, which suggests that the possession of rosewood rather than mahogany, or imitation silver rather than sterling, was a variation shaped not merely by wealth but by cultural capital. This exposes strands of contingency, competition and compromise in middle class expression.

Identifying the drivers behind housing preferences of first time owners

Purpose – The purpose of this paper is to provide a rare insight into the motivation behind first-time buyers when looking to purchase their first home. The factors driving demand preferences for detached housing are constantly changing and difficult to measure, and often deemed to be a complex bundle of attributes.

Design/methodology/approach – The research in this paper is based on interviews with purchasers at a series of locations across Melbourne, Australia, who were actively seeking to purchase a home for the first time. The data were analysed using factor analysis to identify the core decision criteria in a new house that were most sought after.

Findings – The findings in this paper confirmed that “financial” issues accounted for approximately 30 percent of the actual decision by first-time buyers to purchase housing, where decisions relating to the timing and choice of housing are dependent on “site-specific” factors.

Research limitations/implications – The research in this paper is aimed specifically at first time buyers only and the influencing factors behind their purchasing decisions.

Practical implications – The paper shows that, if consideration is given to the characteristics that first-time owners are looking for, providers of new housing would be better equipped to meet this demand and maximise construction efficiency.

Originality/value – In the paper the emphasis was placed on identifying and analysing the decision criteria behind first-time buyers, which provided an invaluable insight into their concept of a suitable residence. Rather than analysing sales transactions after they have been completed, this research considers aspects of new houses that first-time owners are actively searching for, prior to making their purchase.

Characterization of the moisture absorption and thermal ageing behaviour of polymeric composite systems using Raman spectroscopy

Advanced polymeric materials and their respective composites are fast becoming one of the world's most frequently used engineering materials. They find application in the manufacture of e.g. boat hulls, high performance motor vehicles, aircraft components and sports goods. Their high specific strength and specific stiffness give them the edge in applications where weight savings are critical, but their long-term durability is often questioned. These materials are susceptible to environmental conditions such as temperature and humidity. There is also a lack of relevant data, due to the long time-scales required for testing. In this study, the Raman technique has been used to monitor the degradation of two composite systems, namely: a rubber toughened vinylester material used in the marine industry and a high temperature bismaleimide/carbon fibre aerospace composite. Preliminary Raman studies show that the toughening rubber particles dispersed in the cured vinylester resin are leached out during hygrothermal ageing. The weight gain during ageing suggests that this leaching process occurs concurrently with the absorption of water molecules. An increase in the degree of cross-linking is observed when bismaleimide/carbon fibre composite is aged at high temperature. This cross- linking tendency decreases with increasing depth within the carbon fibre bundle.

Wireless instantaneous neurotransmitter concentration system-based amperometric detection of dopamine, adenosine, and glutamate for intraoperative neurochemical monitoring - laboratory investigation

Object  In a companion study, the authors describe the development of a new instrument named the Wireless Instantaneous Neurotransmitter Concentration System (WINCS), which couples digital telemetry with fast-scan cyclic voltammetry (FSCV) to measure extracellular concentrations of dopamine. In the present study, the authors describe the extended capability of the WINCS to use fixed potential amperometry (FPA) to measure extracellular concentrations of dopamine, as well as glutamate and adenosine. Compared with other electrochemical techniques such as FSCV or high-speed chronoamperometry, FPA offers superior temporal resolution and, in combination with enzyme-linked biosensors, the potential to monitor nonelectroactive analytes in real time.

Methods  The WINCS design incorporated a transimpedance amplifier with associated analog circuitry for FPA; a microprocessor; a Bluetooth transceiver; and a single, battery-powered, multilayer, printed circuit board. The WINCS was tested with 3 distinct recording electrodes: 1) a carbon-fiber microelectrode (CFM) to measure dopamine; 2) a glutamate oxidase enzyme–linked electrode to measure glutamate; and 3) a multiple enzyme–linked electrode (adenosine deaminase, nucleoside phosphorylase, and xanthine oxidase) to measure adenosine. Proof-of-principle analyses included noise assessments and in vitro and in vivo measurements that were compared with similar analyses by using a commercial hardwired electrochemical system (EA161 Picostat, eDAQ; Pty Ltd). In urethane-anesthetized rats, dopamine release was monitored in the striatum following deep brain stimulation (DBS) of ascending dopaminergic fibers in the medial forebrain bundle (MFB). In separate rat experiments, DBS-evoked adenosine release was monitored in the ventrolateral thalamus. To test the WINCS in an operating room setting resembling human neurosurgery, cortical glutamate release in response to motor cortex stimulation (MCS) was monitored using a large-mammal animal model, the pig.

Results   The WINCS, which is designed in compliance with FDA-recognized consensus standards for medical electrical device safety, successfully measured dopamine, glutamate, and adenosine, both in vitro and in vivo. The WINCS detected striatal dopamine release at the implanted CFM during DBS of the MFB. The DBS-evoked adenosine release in the rat thalamus and MCS-evoked glutamate release in the pig cortex were also successfully measured. Overall, in vitro and in vivo testing demonstrated signals comparable to a commercial hardwired electrochemical system for FPA.

Conclusions  By incorporating FPA, the chemical repertoire of WINCS-measurable neurotransmitters is expanded to include glutamate and other nonelectroactive species for which the evolving field of enzyme-linked biosensors exists. Because many neurotransmitters are not electrochemically active, FPA in combination with enzyme-linked microelectrodes represents a powerful intraoperative tool for rapid and selective neurochemical sampling in important anatomical targets during functional neurosurgery.

My place: exploring children's place-related identities through reading and writing

This paper considers how children perceive and represent their placed-related identities through reading and writing. It reports on the findings of an 18-month interdisciplinary project, based at Cambridge University Faculty of Education, which aimed to consider children’s place-related identities through their engage- ment with, and creation of, texts. This paper will discuss the project, its interdisciplinary theoretical framework, and the empirical research we conducted with two classes in primary schools in Eastern England. A key text used in our research was My Place by Nadia Wheatley and Donna Rawlins. Drawing on our interdisciplinary theoretical framework, particularly Doreen Massey’s notion of place as a bundle of trajectories, and Louise Rosenblatt’s notion of the transaction between the reader and the text, this paper will examine pages from My Place, children talking about how this text connects with them, children talking about their sense of place, and maps and writing the children produced based on their place.

Influence of the sonication temperature on the debundling kinetics of carbon nanotubes in Propan-2-ol

The effect of sonication temperature on the debundling of carbon nanotube (CNT) macro-bundles is reported and demonstrated by analysis with different particle sizing methods. The change of bundle size over time and after several comparatively gentle sonication cycles of suspensions at various temperatures is reported. A novel technique is presented that produces a more homogeneous nanotube dispersion by lowering the temperature during sonication. We produce evidence that temperature influences the suspension stability, and that low temperatures are preferable to obtain better dispersion without increasing damage to the CNT walls.

Auditor industry specialisation, service bundling and partner effects in a mining-dominated city

This study examines auditor industry specialisation effects in Perth, a remote mining town in Australia characterised by a large number of small, homogeneous firms. We consider the impact of leadership by the non-Big 4 auditor BDO Kendalls (BDO) for a sample of 371 mining development stage entities (MDSE's). After controlling for factors known to determine audit fees, we find no evidence of auditor industry leadership fee premiums accruing to (BDO), a result robust to a range of sensitivity tests including the broadening of tests Australia-wide. However, when the dependent variable is redefined to the total 'bundle' of services provided by the audit firm (including audit and non-audit fees), the industry leader is shown to earn a fee premium suggesting BDO uses audits as a conduit to supply higher margin non-audit services. Our findings suggest that strategic pricing by industry leaders may not be confined to Big 4 firms.

Permeability mapping in porous media by magnetization prepared centric-scan SPRITE

The ability of porous media to transmit fluids is commonly referred to as permeability. The concept of permeability is central for hydrocarbon recovery from petroleum reservoirs and for studies of groundwater flow in aquifers. Spatially resolved measurements of permeability are of great significance for fluid dynamics studies. A convenient concept of local Darcy’s law is suggested for parallel flow systems. The product of porosity and mean velocity images in the plane across the average flow direction is directly proportional to permeability. Single Point Ramped Imaging with T 1 Enhancement (SPRITE) permits reliable quantification of local fluid content and flow in porous media. It is particularly advantageous for reservoir rocks characterized by fast magnetic relaxation of a saturating fluid. Velocity encoding using the Cotts pulsed field gradient scheme improves the accuracy of measured flow parameters. The method is illustrated through measurements of 2D permeability maps in a capillary bundle, glass bead packs and composite sandstone samples.

Consumer perceptions of bundles and time-limited promotion deals: Do contracts matter?

Marketers use various types of deals to positively influence consumers' product evaluations. Across two experiments, we manipulated print advertisements to examine whether the commonly used deal content of both bundling and time-limited promotions affect consumers' perceived confusion, risk and value. In study 1, the influence of this content was tested in the context of a 2-year telecommunications (telco) contract. Here, consumers associated a three-item bundle with greater perceived value than a single item, but perceived value was reduced and risk heightened when it was only available for a limited time. We speculate that this is because of the long-term nature of the contract. Study 2 removed the contract restriction, examining the bundling of a video game console and game(s), again with a time-limited promotion. However, in this context, we failed to locate any interaction effects. It appears that consumers further appraise the drawbacks of a long-term telco contract when accompanied by a time-limited promotion and may perceive the switching costs for study 1 three-item telco bundle to be particularly risky. Our studies represent the first empirical investigation of the effect on consumers' perceptions of offering a bundle in conjunction with a time-limited promotion. Testing these effects in contract and no contract conditions adds to the contribution of our studies by delineating a boundary condition. From a managerial perspective, our findings are thought-provoking in respect to information integration, or how consumers process different deal content together.