Toughened electrospun nanofibers from crosslinked elastomer-thermoplastic blends

A crosslink-able elastomeric polyester urethane (PEU) was blended with a thermoplastic, polyacrylonitrile (PAN), and electrospun into nanofibres. The effects of the PEU/PAN ratio and the crosslinking reaction on the morphology and the tensile properties of the as-spun fibre mats were investigated. With the same overall polymer concentration (9 wt %), the nanofibre containing higher composition of PEU shows a slight decrease in the average fibre diameter, but the tensile strength, the elongation at break and tensile modulus of the nanofibre mats are all improved. These tensile properties are further enhanced by slight crosslinking of the PEU component within the nanofibres.

Thermoplastic film from superfine wool powder

In this paper a research work is described in which superfine wool powder was plasticised by glycerol and hot-pressed into a kind of thermoplastic film. SEM photos show that the powder is moulded into a smooth surface and is conglutinated into a continuous phase in the cross-section of the film. The glycerol content, moulding pressure, temperature and moulding time were changed in the moulding process. The sizes and thickness aw well as tensile strength, modulus, breaking elongation and breaking energy of the films were also tested to investigate the thermoplasticity and mechanical properties of the films. The best moulding techniques included a glycerol content of 30%, a moulding pressure of 5 MPa, a temperature of 160 °C and a moulding time of 5 minutes.

Structural and material properties of a rapidly cured thermoplastic-toughened epoxy system

Thermoplastic-toughened epoxy resins are widely used as matrices in modern composite prepreg systems. Rapid curing of thermoplastic-toughened epoxy matrix composites results in different mechanical properties. To investigate the structure–property relationship, we investigated a poly(ether sulfone)-modified triglycidylaminophenol/ 4,4'-diamino diphenyl sulfone system that was cured at different heating rates. An intermediate dwell was also applied during the rapid heating of the thermoplasticmodified epoxy system. We found that a higher heating rate led to a larger domain size of the phase-separated macrostructure and also facilitated more complete phase separation. The intermediate dwell helped phase separation to proceed even further, leading to an even larger domain size of the macrostructure. A carbon-fiber-reinforced polymer matrix composite prepreg based on the poly(ether sulfone)-modified multifunctional epoxy system was cured with the same schedule. The rapidly heated composite laminates exhibited higher mode I delamination fracture toughness than the slowly heated material.

Study on thermoplastic-modified multifunctional epoxies : influence of heating rate on cure behaviour and phase separation

The effect of heating rate on the cure behaviour and phase separation of thermoplastic-modified epoxy systems was investigated. Polyethersulphone (PES) modified multifunctional epoxies, triglycidyl-aminophenol (TGAP) and tetraglycidyldiaminodiphenylmethane (TGDDM), as well T300/914 prepreg were used. It was shown that heating rate had a significant influence on the cure kinetics and phase structures of investigated systems. Greater heating rate causes higher epoxy conversion. The domain size of the macrophases formed from phase separation increases with the increase of heating rate. A more complete phase separation is achieved by fast heated thermoplastic-modified epoxy blends.

Modification of thermoplastic coatings for improved cathodic disbondment performance on a steel substrate : a study on failure mechanisms

The effect of blending two different materials with a medium density polyethylene for use as pipe coatings is presented. The influence of such blending on properties such as cathodic disbondment (CD) and wet adhesion on steel is investigated. The components blended include a functionalised polyethylene (PE) containing the polar functionality, maleic anhydride (MAH) and an amorphous elastomer, ethylene-propylene-diene terpolymer (EPDM). It was found that modification of PE with small amount (2.5–3 wt%) of either blended MAH-g-PE or EPDM resulted in a significant improvement in CD performance and wet adhesion strength. The mode of failure and disbondment mechanism was investigated using energy dispersive X-ray spectroscopy (EDXS) and X-ray photoelectron spectroscopy (XPS). The greater resistance of migration of sodium ions increases with the incorporation of the modifiers, and it is proposed that this results in an increase in CD performance.

School day segmented physical activity patterns of high and low active children

Background

Variability exists in children's activity patterns due to the association with environmental, social, demographic, and inter-individual factors. This study described accelerometer assessed physical activity patterns of high and low active children during segmented school week days whilst controlling for potential correlates.
Methods

Two hundred and twenty-three children (mean age: 10.7 +/- 0.3 yrs, 55.6% girls, 18.9% overweight/obese) from 8 north-west England primary schools wore ActiGraph GT1M accelerometers for 7 consecutive days during autumn of 2009. ActiGraph counts were converted to minutes of moderate (MPA), vigorous (VPA) and moderate-to-vigorous (MVPA) physical activity. Children were classified as high active (HIGH) or low active (LOW) depending on the percentage of week days they accumulated at least 60 minutes of MVPA. Minutes spent in MPA and VPA were calculated for school time and non-school time and for five discrete school day segments (before-school, class time, recess, lunchtime, and after-school). Data were analysed using multi-level modelling.
Results

The HIGH group spent significantly longer in MPA and/or VPA before-school, during class time, lunchtime, and after-school (P < .05), independent of child and school level factors. The greatest differences occurred after-school (MPA = 5.5 minutes, VPA = 3.8 minutes, P < 0.001). MPA and VPA were also associated with gender, BMI z-score, number of enrolled children, playground area per student, and temperature, depending on the segment analysed. The additive effect of the segment differences was that the HIGH group accumulated 12.5 minutes per day more MVPA than the LOW group.
Conclusions

HIGH active children achieved significantly more MPA and VPA than LOW active during four of the five segments of the school day when analyses were adjusted for potential correlates. Physical activity promotion strategies targeting low active children during discretionary physical activity segments of the day, and particularly via structured after-school physical activity programs may be beneficial.

Electrostatically confined plasma in segmented hollow cathode geometries for surface engineering

A segmented hollow cathode (SHC) geometry was used for electrostatic confinement of plasma, and surface engineering treatments were conducted in this arrangement. The assessed processes included plasma nitriding, reactive deposition of sputtered material, and deposition of carbonaceous films by plasma-enhanced chemical vapor deposition with a bipolar pulsed-dc power supply on steel substrates. The treated specimens exhibited uniform surface morphology and deposition layers. Characterization techniques included optical microscopy, scanning electron microscopy with energy dispersive X-ray capability, and X-ray diffraction. The advantages and potential applications of the SHC arrangement are discussed in view of these results.

Leisure experiences in tourist attractions : exploring the motivations of local residents

This study was conducted to explore leisure motivations with regard to tourist attractions. A survey of a convenience sample of residents of Melbourne, Australia, was conducted. The sample was then segmented based on the likelihood of visiting a cross-section of Melbourne's tourist attractions in the next 6 months. Analysis using Unger and Kernan's (1983) Subjective Leisure Scale (SLS) was then undertaken to explore whether there were differences across the segments in terms of their leisure motivations. The results highlight that, within this context, intrinsic satisfaction, perceived freedom and arousal emerged as stronger underlying dimensions of motivations to visit tourist attractions, rather than mastery, spontaneity and involvement. This information provides insights for marketers of tourist attractions with regard to what residents are seeking when they visit local tourist attractions. The information can be used to develop more positive experiences at tourist attractions for this important sector of the market.

Sports-events, tourism and destination marketing strategies: an Australian case study of Athens 2004 and its media telecast

The focus of this study was the media telecast of the Athens 2004 Summer Olympic Games. The study explored the efficacy of the Australian telecast in developing positive perceptions and attitudes of Greece as a tourist  destination and was origin-based—in that a survey was undertaken of a sample of Australian residents (n = 350). Participants were segmented based on their post-consumption perceptions of Greece. Four segments were identified and labelled—'extremely positive' (n = 75), 'highly positive' (n = 153), 'positive' (n = 83) and 'negative' (n = 29). Statistical differences were found between the segments based on whether attitudes towards Greece had improved as a result of their consumption of the media telecast of the Athens 2004 Olympic Games (Athens 2004). To gain insights into this phenomenon, open-ended responses provided by segment members were then analysed.

Across the sample, 38.7% of respondents indicated that their overall attitude towards Greece as tourist destination changed as a result of their consumption of the telecast of Athens 2004. Considering that the attitudes of participants in the current study improved, not as a result of first-hand experiences at the destination, but as a result of their vicarious experiences of the destination through consumption of a media telecast of a special event, the results provide insights to the efficacy of this particular telecast in developing positive attitudes with regard to Greece as a tourist destination. The results of this study could be used a benchmark for future event-related destination marketing strategies. Similarities and differences emerged between the segments with regard to the reasons as to why members of each of the clusters attitudes towards Greece as a tourist destination had improved as a result of their consumption of the telecast. While their responses appeared to be similar, the frequency in which the concepts emerged for each of the segments varied intensity. The key issues that emerged for the four clusters were the appearance of Greece; culture and history of Greece; capacity, or 'hostability', of Greece to stage the Athens 2004; and infrastructure in Greece.

Grid-based method for ranking images with multiple objects

One of the content-based image retrieval techniques is the shape-based technique, which allows users to ask for objects similar in shape to a query object. Sajjanhar and Lu proposed a method for shape representation and similarity measure called the grid-based method [1]. They have shown that the method is effective for the retrieval of segmented objects based on shape. In this paper, we describe a system which uses the grid-based method for retrieval of images with multiple objects. We perform experiments on the prototype system to compare the performance of the grid-based method with the Fourier descriptors method [2]. Preliminary results have been presented.