Patterned growth of carbon nanotubes on Si substrates without predeposition of metal catalysts

Aligned carbon nanotubes (CNTs) can be readily synthesized on quartz or silicon-oxide-coated Si substrates using a chemical vapor deposition method, but it is difficult to grow them on pure Si substrates without predeposition of metal catalysts. We report that aligned CNTs were grown by pyrolysis of iron phthalocyanine at 1000 °C on the templates created on Si substrates with simple mechanical scratching. Scanning electron microscopy and x-ray energy spectroscopy analysis revealed that the trenches and patterns created on the surface of Si substrates were preferred nucleation sites for nanotube growth due to a high surface energy, metastable surface structure, and possible capillarity effect. A two-step pyrolysis process maintained Fe as an active catalyst.

Nucleation and growth of carbon nanotubes in a mechano-thermal process

Separate nucleation and growth processes of carbon nanotubes were found in a mechano-thermal method in which carbon nanotubes are produced by first mechanical milling of graphite powder at room temperature and subsequent thermal annealing up to 1400 °C. The ball-milled graphite contains nucleation structures (nanosized metal particles and deformed (0 0 2) layers containing pentagons), and disordered carbon as a free carbon atom source. The subsequent annealing activates the growth of two types of multi-walled nanotubes in the absence of carbon vapor. Thin nanotubes (diameter <20 nm) are formed via crystallization of the disordered carbon with the preferred formation of the (0 0 2) basal planes. Thick nanotubes (diameter >20 nm) are formed through a metal catalytic solution–precipitation process (solid–liquid–solid). In both cases, carbon nanotubes grew out from disordered carbon particles with closed tips.

Controlled growth of zinc nanowires

Zinc nanowires have been synthesized by heating a mixture of boron and zinc oxide (ZnO) powders at 1050 °C under a nitrogen atmosphere. The influences of the gas flow rate and the substrate character on the nanowire formation were investigated. It was found that higher-flow rate of gas led to the formation of thinner nanowires; while lower-flow rate of gas produced thicker nanowires and even particles due to the higher partial pressure of Zn vapor in this case. Zn nanowires can be produced on alumina and quartz substrates, but not on a stainless-steel substrate under the same or different synthetic conditions. Photoluminescence measurements were conducted on Zn nanowires and particles and weak emission bands at 482 and 493 nm were observed, which may be contributed by the thin ZnO film on the nanowire surface.

Influence of nitriding gases on the growth of boron nitride nanotubes

Boron nitride (BN) nanotubes of different sizes and tubular structures exhibit very different mechanical and chemical properties, as well as different applications. BN nanotubes of different sizes and nanostructures have been produced in different nitriding gases in a milling and annealing process, in which elemental boron powder was first milled in NH₃ for 150 h and subsequently annealed at 1,200 °C for 6 h. The influence of nitriding gases was investigated by using N₂, NH₃, N₂–H₂ mixture gases. A relatively slow nitriding reaction in NH₃ gas leaded to a 2D growth of BN (002) basal planes and the formation of thin BN nanotubes without the help of metal catalysts. Fast nitriding reactions occurred in N₂ or N₂–H₂ mixture gases, catalyzed by metal particles, resulted in 3D crystal growth and the formation of many large cylindrical and bamboo tubes.

In situ growth of Soletellina alba (Bivalvia: Psammobiidae) in response to detrital supply and mouth status in a seasonally-closed estuary

The supply of detritus is an important food source for many soft-sediment invertebrates, but its importance for their growth and condition is rarely, if ever, tested directly using manipulative field experiments. Therefore, we designed such a study to: (1) test the importance of fine particulate organic matter for the growth and condition of the infaunal bivalve Soletellina alba; (2) indirectly test the feeding mode of S. alba, which has been assumed to be a deposit feeder like other members of the same superfamily (Tellinoidea); (3) compare growth rates across two summers with contrasting patterns of estuary mouth opening/closing; and (4) compare the condition of individuals used in two field studies (i.e. present versus past) and a past laboratory study. Neither growth nor condition differed when organic content of the sediments was varied, which suggests that S. alba is either a suspension feeder or capable of switching modes of feeding. There was considerable interannual variation in growth with greater growth occurring during the summer with a longer period of mouth opening. This suggests that periods of mouth closure may reduce secondary production within seasonally-closed estuaries. Potential artefacts associated with laboratory trials were also identified, with laboratory bivalves exhibiting poorer condition than those used in two field trials. The present study provides no evidence that variable quantities and qualities of organic matter within the sediments influence the growth and condition of S. alba, but future studies should focus on food supplied via the water column when the estuary is open versus closed.

Cultural factors behind the growth of e-learning in Malaysia Academic guanxi

This paper aims to discover and examine ways in which cultural factors shape the adoption and use of information technology for online teaching. This research focuses on influential early adopters in the tertiary education sector in Malaysia who have become change-agents by inspiring small networks of their peers. The study examines the concept of guanxi to understand the operation of trust and inspiration in networking and teamwork in the Asian academic environment. This study points to the importance of developing guanxi, through the middle-down nurturing of peer networks, in developing a rich and rewarding environment for the development of online teaching.

Higher education services exports : sources of growth of Asian students in US and UK

The paper reviews the recent trends and current developments in the global higher education market with a particular focus on growth of Asian students studying in US and UK. Using pool cross section-time series data over the 1985–2003 period, it is found that different factors affect students from different countries differently. This suggests that the marketing strategies of offshore higher education providers need to be tailored to the specific needs of different markets in order to be successful. The emergence of a number of new players in the higher education export market is also rapidly becoming a major threat to the traditional higher education service exporters.

Teaching Zambian traditional birth attendants to monitor growth of infants : evaluation of an education program

The high infant mortality in Zambia is largely attributable to malnutrition. It is exacerbated by the inability of mothers to recognise threats to nutritional status and take corrective action. Advice in ‘Health Centres’ is often inaccessible to mothers. The Traditional Birth Attendants (TBAs) work with pregnant women in local communities, and the purpose of this study was to develop and implement an educationprogram in growth monitoring and nutrition for the TBAs and then to evaluate its effects. Twenty five TBAs from two peri-urban areas of Kitwe were enrolled in this pilot study and eighteen completed the program. The researcher developed and taught a program to the TBAs over ten days. A pretest was given before the teaching program to enable the researcher to obtain information about the knowledge and skills of the TBAs. Following the teaching program the TBAs were re-tested, with the same questionnaire. Focus groups were conducted to enable the TBA to provide information on the teaching materials and the education program. The TBAs then returned to their communities and put into practice the skills and knowledge they had learned for six months. Their practice was monitored by a trained Public Health Nurse. The researcher also surveyed 38 pregnant women about their knowledge of growth monitoring and nutrition before the TBAs went into the field to work with their local communities. The same questionnaire used with the pregnant women was administered to 38 new mothers with children aged 0 to 6 months to gain information of their knowledge and skills following the work of the TBAs. The program was evaluated by assessing the extent to which TBAs knowledge and skills were increased, the knowledge and understanding of a selection of their clients and the rates of malnutrition of infants in the area under study. The results from the research clearly indicated that the teaching program on growth monitoring and nutrition given to the selected group of TBAs had a positive effect on their knowledge and skills. It was found that the teaching developed their knowledge, practical skills, evaluative skills. That they were able to give infants’ mothers sound advice regarding their children’s nutrition was revealed by the mother’s increased knowledge and the decrease in numbers of malnourished children in the study areas at the conclusion of the research. The major outcomes from the study are: that Zambian TBAs can be taught to carry out an expanded role; field experience is a key factor in the teaching program; making advice available in local communities is important; and preliminary data on the Zambian experience were generated. Recommendations are: The pilot program should be expanded with continuing support from the Health Department. Similar educational programs should be introduced into other areas of Zambia with support from the Ministry of Health. That in administering a teaching program: Sufficient time must be allocated to practical work to allow poorly educated women to attain the basic skills needed to master the complex skills required to competently reduce faltering in their communities. The teaching materials to illustrate nutritional principles for feeding programs must be developed to suite locally available foods and conditions. Methods of teaching should suit the local area, for example, using what facilities are locally available. The timing of the teaching program should be suitable for the TBAs to attend. This may vary from area to area, for example it may be necessary to avoid times traditionally given to fetching water or working in the fields. For similar reasons, the venue for the teaching program should be suitable to the TBAs. The teachers should go into the TBAs’ community rather than causing disruption of the TBAs’ day by expecting them to go to the teacher. Data should be collected from a larger group of TBAs and clients to enable sophisticated statistical analysis to complement data from this pilot program. The TBAs should be given recognition for their work and achievement. This is something which they asked for. They do not ask for payment, rather acknowledgment through regular follow up and approbation.

Weaning and growth of Anguilla australis glass eels and elvers

Anguilla australis glass eels proved to be resilient and present strong aquaculture potential. General husbandry techniques, anaesthesia and prophylactic treatments were established for glass eels between 0.1 g and 2.0 g and elvers between 2.0 g and 8.0 g, caught in rivers and estuaries along the South East Coast of Victoria. The protozoan parasites Ichthyobodo and Trichodina were found to be present on arrival to the hatchery developed during different rearing treatments, and were successfully eradicated. A. australis glass eels accepted artificial food, but it was recommended first be fed a preweaning diet of minced fish flesh. A weaning regime from minced fish flesh to commercially available eel grower mash, over 15 days was established. Growth rate proved to be highly variable, both between and within groups. The highest growth rate of 2.71%/day was found when the natural diet of minced fish and Artemia was fed. The maximum growth rate when reared on an artificial diet of 1.63%/day was observed at 25°C. Growth was affected by the presence or absence of a preweaning diet, weaning diet, weaning period, temperature, but not by size or density. Once weaned, glass eels were found to perform better on commercially available grower mash than on the minced fish flesh, which was used to aid in weaning them to artificial diets. Of the water quality parameters measured stocking density was found to affect pH, Total Ammonia Nitrogen, Total Phosphorus, and Dissolved Oxygen, through not to an extent which affected growth.

Frequency of shearing increases growth of fibre and changes objective and subjective attributes of Angora goat fleeces

The impact of genotype and of frequency and timing of shearing, on mohair attributes and production of modern Angora goats was studied. Goats in the southern hemisphere grazed pastures between February 2004 and 2006. There were seven shearing treatments by three genetic strains with four or eight replicates of individual goats. Treatments were: three different 6-month shearing intervals and two of 12-month shearing intervals with different months of shearing, a 7-month winter shearing interval and a 3-month shearing interval. Genetic strain was based on sire line: 1·0 South African; 1·0 Texan; and Mixed 0·5 South African and 0·5 Texan. Annual greasy mohair production was 5·08 kg, and average clean fleece production was 4·37 kg. The Angora goats produced an annual clean fleece equivalent to 0·122 of their mean fleece-free live weight which was equal to 0·34 g/kg/day. Measurements were analysed over the period of spring 2004 shearing to spring 2005 shearing, excluding the June–December shearing treatment. Increased frequency of shearing increased fleece growth and affected 13 objective and subjective attributes of mohair that were evaluated including clean washing yield, fibre diameter and fibre diameter variation, incidence of medullated fibres, staple length, fibre curvature, crimp frequency, style, staple definition, staple fibre entanglement and staple tip shape. The direction of these effects were generally favourable and for most attributes the magnitude of the response was linear and commercially important. Each additional shearing resulted in an additional 149 g of clean mohair representing 0·034 of the annual clean mohair production. This increase was associated with a 0·6 cm increase in staple length and 0·32 μm increase in mean fibre diameter. In conclusion, Angora goats shorn less frequently grew less mohair that was more likely to be entangled in spring. Managers of Angora goats should take note of these findings.