Mass production of nanofibers from a spiral coil

In this study, we have demonstrated that a rotating metal wire coil can be used as a nozzle to electrospin nanofibers on a large-scale. Without using any needles, the rotating wire coil, partially immersed in a polymer solution reservoir, can pick up a thin layer of charged polymer solution and generate a large number of nanofibers from the wire surface simultaneously. This arrangement significantly increases the nanofiber productivity. The fiber productivity was found to be determined by the coil dimensions, applied voltage and polymer concentration. The dependency of fiber diameter on the polymer concentration showed a similar trend to that for a conventional electrospinning system using a syringe needle nozzle, but the coil electrospun fibers were thinner with narrower diameter distribution. The profiles of electric field strength in the coil electrospinning was calculated and showed concentrated electric field intensity on the top wire surface.

Extending light-weighting and mass-production of ultra high strength steels via condition-based maintenance

The use of ultra high strength steels (UHSS) in the automotive industry presents a significant opportunity for continued vehicle light-weighting, due to possible strength-to-weight improvements of three to four times that of conventional sheet steel grades. This performance benefit is achievable whist maintaining most of the advantages of low-cost mass-production associated with the cold stamping of sheet steel for automotive body components. However, the introduction of UHSS can result in significantly increased wear of the stamping tools, which is difficult to predict at the design stage and can lead to unexpected process failure during mass-production. Therefore, there is a need to be able to monitor and predict the onset of severe wear, such that the best course of condition-based maintenance can be scheduled and unscheduled stoppages due to tool wear eradicated. This paper describes a novel active monitoring system that is being developed by researchers at Deakin University, The Australian National University and Ford Motor Company, Asia Pacific and Africa. The aim of the active monitoring system is to detect the initial onset of a change of state, such as wear, through the measurement of variables such as punch force and audio signals. A semi-industrial stamping process, using a progressive die setup and high strength steel sheet with hardened tool steel tooling, is the experimental basis for the initial model and system development.

Scalable production of wrinkled and few-layered graphene sheets and their use for oil and organic solvent absorption

High-quality wrinkled and few-layered graphene sheets have been produced via a mechano-thermal exfoliation process for a simple, effective and low-cost mass production. Graphene sheets were produced by first ball milling of graphite with ammonium chloride followed by thermal annealing at 800 °C in nitrogen gas. The few layered graphene sheets show highly efficient selectivity and capacity for the absorption of petroleum products as well as organic solvents such as ethanol, cyclohexane and chloroform (up to 82, 42 and 98 times of their own weight, respectively). The saturated few-layered graphene sheets can be cleaned for reuse by simply burning in air. The low-cost strategy for mass production and easy recycling routes demonstrate the great potential of few-layered graphene sheets for oil removal.

Scaling up the production rate of nanofibers by needleless electrospinning from multiple ring

Mass production of nanofibers is crucial in both laboratory research and industry application of nanofibers. In this study, multiple ring spinnerets have been used to generate needleless electrospinning. Multiple polymer jets were produced from the top of each ring in the spinning process, resulting in thin and uniform nanofibers. Production rate of nanofibers increased gradually with the increase of the number of rings in the spinneret. Spinning performance of multiple ring electrospinning, namely the quality and production rate of the as-spun nanofibers, was dependent on experimental parameters like applied voltage and polymer concentration. Electric field analysis of multiple ring showed that high concentrated electric field was formed on the surface of each ring. Fiber diameter together with production rate of needleless electrospinning was dependent on the strength and distribution of the electric field of the spinneret. Needleless electrospinning from multiple ring can be further applied in both laboratory research and industry where large amount of nanofibers must be employed simultaneously. © 2014 The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Evaluating irradiation dose for sterility induction and quality control of mass-produced fruit fly Bactrocera tryoni (Diptera : Tephritidae)

The sterile insect technique has been routinely used to eradicate fruit fly Bactrocera tryoni (Froggatt) incursions. This study considers whether fly quality in a mass-rearing facility can be improved by reducing irradiation doses, without sacrificing reproductive sterility. Pupae were exposed to one of five target irradiation dose ranges: 0, 40-45, 50-55, 60-65, and 70-75 Gy. Pupae were then assessed using routine quality control measures: flight ability, sex ratio, longevity under nutritional stress, emergence, and reproductive sterility. Irradiation did not have a significant effect on flight ability or sex ratio tests. Longevity under nutritional stress was significantly increased at 70-75 Gy, but no other doses differed from 0 Gy. Emergence was slightly reduced in the 50-55, 60-65, and 70-75 Gy treatments, but 40-45 Gy treatments did not differ from 0 Gy, though confounding temporal factors complicate interpretation. Reproductive sterility remained acceptable (> 99.5%) for all doses--40-45 Gy (99.78%), 50-55 Gy (100%), 60-65 Gy (100%), and 70-75 Gy (99.99%). We recommend that B. tryoni used in sterile insect technique releases be irradiated at a target dose of 50-55 Gy, providing improved quality and undiminished sterility in comparison with the current 70-75 Gy standard while also providing a substantial buffer against risk of under dosing.

Synthesis of ZnO nanowires using ball-milling and annealing method

Nanowires represent a new class of ZnO morphologies with many exiting new properties and applications. The research in the synthesis and characterization of ZnO nanowires has received enormous attention in recent years. However, most synthesis methods using vapor deposition process can only produce small amount of sample, mass production has not been achieved yet. Large-quantity production of ZnO nanowires needs to be realized for large-scale property and application studies. One of the promising approaches to the large scale synthesis is a ball-milling and annealing method. This paper first introduces several common synthesis methods of ZnO nanowires and then summarizes the one dimensional nanomaterials produced by the ball milling and annealing method. Finally, some preliminary results of ZnO nanowire synthesis are presented.

One-dimensional nanomaterials synthesized using high-energy ball milling and annealing process

One-dimensional (1D) nanomaterials including nanotubes, nanowires and nanorods have many new properties, functionalities and a large range of promising applications. A major challenge for these future industrial applications is the large-quantity production. We report that the ball milling and annealing process has the potential to achieve the mass production. Several examples including C, BN nanotubes and SiC, Zn nanowires are presented to demonstrate such capability. In addition, both size and structure of 1D nanomaterials can be controlled by varying processing conditions. New growth mechanisms involved in the process have been investigated and the high-energy ball milling has an important role in the formation of these 1D nanomaterials.

Needleless electrospinning. I. A comparison of cylinder and disk nozzles

In this study, we demonstrated the needleless electrospinning of poly(vinyl alcohol) (PVA) nanofibers with two nozzles, a rotating disk and a cylinder, and examined the effect of the nozzle shape on the electrospinning process and resultant fiber morphology. The disk nozzle needed a relatively low applied voltage to initiate fiber formation, and the fibers were mainly formed on the top disk edge. Also, the PVA concentration had little influence on the disk electrospinning process (up to 11 wt %). In comparison, the cylinder electrospinning showed a higher dependence on the applied voltage and polymer concentration. The fibers were initiated from the cylinder ends first and then from the entire cylinder surface only if the applied voltage were increased to a certain level. With the same polymer solution, the critical voltage needed to generate nanofibers from the disk nozzle was lower than that needed to generate nanofibers from the cylinder. Both electrospinning systems could produce uniform nanofibers, but the fibers produced from the disk nozzle were finer than those from the cylinder when the operating conditions were the same. A thin disk (8 cm in diameter and 2 mm thick) could produce nanofibers at a rate similar to that of a cylinder of the same diameter but 100 times wider (i.e., 20 cm long). Finite element analysis of electric field profiles of the nozzles revealed a concentrated electric field on the disk edge. For the cylinder nozzle, an uneven distribution of the electric field intensity profile along the nozzle surface was observed. The field lines were mainly concentrated on the cylinder ends, with a much lower electric field intensity formed in the middle surface area. At the same applied voltage, the electric field intensity on the disk edge was much higher than that on the cylinder end. These differences in the electric field intensity profiles could explain the differences in the fiber fineness and rate of the nanofibers produced from these two nozzles. These findings will benefit the design and further development of large-scale electrospinning systems for the mass production of nanofibers for advanced applications.

The ultimate sustainable home

The introduction of assembly line techniques to vehicle manufacturing by Henry Ford in the early 1900s dramatically reduced production costs, improved quality and made cars affordable to all. As a consequence people’s lives, cities and society were transformed.
Many attempts have been made to apply vehicle mass production techniques to domestic housing manufacturing, but the success has been limited largely due to underdeveloped manufacturing processes, incomplete integration of building services and limited consideration of environmental performance.
This paper describes an approach that promises to revolutionize the building market in Australia by providing architect designed attractive high quality comfortable modular housing system that incorporates state-of-the-art services and controls. Costs, GHG emissions and material wastage are all substantially less than timber framed housing construction commonly used in Australia.

Titanium oxide nanorods extracted from ilmenite sands

One dimensional titanium oxides (TiO2) nanorods and nanowires have substantial applications in photocatalytic, nanoelectronic, and photoelectrochemical areas. These applications require large quantities of materials and a production technique suitable for future industry fabrication. We demonstrate here a new method for mass production of TiO2 nanorods from mineral ilmenite sands (FeTiO3). In this process, powder mixtures of ilmenite and activated carbon were first ball milled; the milled samples were then heated twice at two different temperatures. First high-temperature annealing produced metastable titanium oxide phases, and subsequent second low-temperature annealing in N2-5%H2 activates the growth of rutile nanorods. This solid-state growth process allows large-quantity production of rutile nanorods.

Electrospinning of polymers for functional nanofibres

Nanofibres have wide applications in energy, environment and medical areas. This project examined new needleless electrospinning technologies for mass production of nanofibres. Functional nanofibres with side-by-side and core-sheath structures have been prepared and their properties have been elucidated.

Synthesis of boron nitride nanotubes by boron ink annealing

Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs.

Needleless electrospinning : influences of fibre generator geometry

The fibre generator shape and dimension are key factors affecting the needleless electrospinning process and fibre fineness. In this work, cylinder with rounded rim, disc and ball were used as spinnerets to electrospin polyvinyl alcohol and polyacrylonitrile solutions. A finite element method was used to analyse how the spinneret geometry affected the electric field generated during electrospinning and the associated changes in fibre diameter and productivity. For cylinder spinnerets, increasing the rim radius reduced the discrepancy of electric field intensity between the cylinder end and middle area, which affected the fibre productivity. The electrospinning failed to operate when the rim radius was over 20 mm. With decreasing cylinder diameter, the electric field intensity in the middle area increased, improving the fibre productivity. Thinner disc spinnerets increased the electric field intensity, resulting in finer nanofibres and higher productivities. Ball spinnerets produced evenly distributed electric field, but failed to electrospin fibres when the diameters were below 60 mm. It has been found that strong and narrowly distributed electric field in the fibre-generating area can significantly facilitate the mass production of quality nanofibres.