18,103 research outputs found
Rapid fabrication of polymer microfluidic systems for the production of artificial lipid bilayers
A polymer microfluidic device has been fabricated using rapid prototyping techniques. The device was built up to allow the formation and subsequent investigation of artificial bilayer lipid membranes (BLMs). A simple dry film photoresist stamp was used to hot emboss microfluidic channels into PMMA films. Laser micromachining was employed to form an aperture into PMMA films. Laser micromachining was employed to form an aperture through the PMMA channels, across which the BLM was later formed. The dry film phororesist was also used as a simple etch mask for the deep etching of glass substrates in buffered HF solutions, which was used in this work for the production of glass embossing stamps. We show that bilayer films can be successfully produced across laser micromachined apertures in PMMA films
Feasibility study of fusion bonding for carbon fabric reinforced Polyphenylene Sulphide by hot-tool welding
In recent years, there is a growing interest in joining techniques for thermoplastic composites as an alternative to adhesive bonding. In this article, a fusion bonding process called hot-tool welding is investigated for this purpose and the used material is a carbon fabric reinforced polyphenylene sulphide. The welds are first observed through a microscope, after which the quality is experimentally assessed using a short three-point bending setup. A comparison is made between the welded specimens and the equivalent hot pressed specimens. It can be concluded that the hot-tool welding process is very promising for the welding of material under study and that the short three-point bending setup proves interesting for evaluating bonds between composite specimens
Organic Single-Crystal Field-Effect Transistors
We present an overview of recent studies of the charge transport in the field
effect transistors on the surface of single crystals of organic
low-molecular-weight materials. We first discuss in detail the technological
progress that has made these investigations possible. Particular attention is
devoted to the growth and characterization of single crystals of organic
materials and to different techniques that have been developed for device
fabrication. We then concentrate on the measurements of the electrical
characteristics. In most cases, these characteristics are highly reproducible
and demonstrate the quality of the single crystal transistors. Particularly
noticeable are the small sub-threshold slope, the non-monotonic temperature
dependence of the mobility, and its weak dependence on the gate voltage. In the
best rubrene transistors, room-temperature values of as high as 15
cm/Vs have been observed. This represents an order-of-magnitude increase
with respect to the highest mobility previously reported for organic thin film
transistors. In addition, the highest-quality single-crystal devices exhibit a
significant anisotropy of the conduction properties with respect to the
crystallographic direction. These observations indicate that the field effect
transistors fabricated on single crystals are suitable for the study of the
\textit{intrinsic} electronic properties of organic molecular semiconductors.
We conclude by indicating some directions in which near-future work should
focus to progress further in this rapidly evolving area of research.Comment: Review article, to appear in special issue of Phys. Stat. Sol. on
organic semiconductor
An exposure fixation technique for skin graft in burns
The primary treatment of burns by exposure, as against that by occlusive dressings, is well established, soundly conceived in its principles and satisfactory in its results. Encouraged by reports of its successful application in the Middle East, the method was introduced into our wards at St. Luke's Hospital, Malta as early as 1952-53, and it has continued to be the standard form of treatment with us for burns of most sites and in the great majority of patients of all ages. Reference is made to a case study of a thirteen year-old male, who has been treated successfully by this technique, whereby the relative benefits are described. This technique has been used on a number of cases requiring skin grafting of both large and small extent, and have been well satisfied with the results. Skin grafts thus treated are more viable, healthier and more supple; they very quickly become indistinguishable from normal skin. No claim to priority is made for the technique described, particularly as the search of the literature has been incomplete. However, it is presented as a well tried and tested method which seeks to follow principles that have proved their worth in the treatment of burns.peer-reviewe
Re-design and fabrication of titanium multi-wall Thermal Protection System (TPS) test panels
The Titanium Multi-wall Thermal Protection System (TIPS) panel was re-designed to incorporate Ti-6-2-4-2 outer sheets for the hot surface, ninety degree side closures for ease of construction and through panel fastness for ease of panel removal. Thermal and structural tests were performed to verify the design. Twenty-five panels were fabricated and delivered to NASA for evaluation at Langley Research Center and Johnson Space Center
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