[en] Subtractive rapid prototyping machine is the most suitable tool to manufacture a polymer based prosthetic part because it is able to achieve a low surface roughness value for a complex and customised part. Many investigations have been conducted to explain the relation among the surface roughness value, the material rate removal, and the subtractive rapid prototyping process parameters. It is important to find the optimum process parameters in order to achieve the most efficient and productive process. However, none of the research found in the literature optimises the subtractive rapid prototyping process parameters in fabricating polycarbonate part. Therefore, this research aims to find the optimum process parameters to achieve the lowest arithmetic average of surface roughness value of the polycarbonate part in maximum material removal rate. In this research, the response surface methodology is implemented to optimised feed rate, step-over, and depth of cut of the subtractive rapid prototyping process. This research finds the feed rate, step-over, and depth of cut values that can be used to achieve the best result in manufacturing of polycarbonate material. (paper)

[en] In conclusion, superhydrophobic surfaces were fabricated by dipping PC plates into CH₂Cl₂ and then coating them through sublimation of TCMS. Because CH₂Cl₂ is a good solvent for dissolving PC plates, the dipping time was very short. Because the nanoporous structure of the PC surface is very labile in organic solvents, we used sublimation of TCMS to coat the surface with low-surface-energy material. After the CH₂Cl₂ treatment, the nanoporous PC plate was successfully coated with TCMS vapor with no deformation of its nanoporous surface structure. The PC plate modified with TCMS had a water contact angle as high as 161 .deg, demonstrating its excellent superhydrophobicity. The technique described here can be applied to the creation of super-hydrophobic nanoporous surfaces on substrates that are labile in organic solvents

[en] Published in summary form only

[en] Bisphenol- A polycarbonates is one of the important commerical products for its out standing physical and mechanical properties. The main disadvantages of this polymer is its susceptibility to Anealing solvent stress cracking and its thermal decomposition at elevated temperatures. The project is concerned with preparation and characterisation of new type of polycarbonates. (11 tabs., 30 figs., 49 refs.)

[en] Subtractive rapid prototyping is fast and automatic three dimensions physical modelling that uses computer aided design model as the input. The dimensional accuracy of the result of the subtractive rapid prototyping is influenced by its process parameters. The aim of this research is to study and then develop a model that shows the influence of depth of cut, feed rate, and step-over on the vertical length error, horizontal length error, and depth error in subtractive rapid prototyping of polycarbonate material. This research implements response surface methodology to develop the model and then followed by the residual tests to evaluate the developed model. The result shows that the increase of the feed rate and the step-over will increase the horizontal dimension error. The most influenced factor on the horizontal dimension error is the step-over. Meanwhile, the vertical dimension error will be affected mostly by the step-over. Last, the depth error is influenced by the feed rate, the step-over, and the depth of cut. The depth of cut is the most critical factor that increases the depth error. The developed models give an insight on how several process parameters of rapid prototyping will influence the dimensional accuracy of a polycarbonate material. Based on the model, efficient resources utilization can be achieved. (paper)

[en] Shrinkage is one of the most important defects in polymeric parts. Although there are several studies in order to control and reduce the shrinkage of polymeric parts, there is no systematic investigation on the shrinkage of injection molded polycarbonate (PC) parts. Therefore, the comprehensive investigation of the shrinkage behavior of PC parts was conducted in the present study. Response surface methodology (RSM) was utilized and PC samples were injection molded in different conditions based on the design of experiments. The shrinkage was studied in both longitudinal and latitudinal directions. The measurements were performed at five points in latitudinal and three points in longitudinal. The shrinkage behavior respect to the distance from the gate was studied. A comparative analysis between the shrinkage across and along the injection direction was performed. Analysis of variance tool of RSM method was utilized in order to recognize most effective parameters on the volumetric shrinkage. A regression model was proposed to estimate the volumetric shrinkage of the PC with high accuracy. The interaction effect of parameters on the volumetric shrinkage was analyzed and different solutions to control the shrinkage were recognized. (paper)

[en] The reliability of outdoor radon concentration measurements using the track-etch technique is affected by the environmental conditions. Studies have been made to improve stability of nuclear tracks in detector material and to achieve a stable dosemeter response. A dosemeter was developed utilizing chemically etched MA-ND/α (CR-39) detector which is thermally insulated and protected against solar irradiation. The calibration showed that its response amounts to 0.21 ± 0.03 tracks m^-2/Bqm^-3 day and was found to be in good agreement with theoretical prediction. (author)

[en] The MACRO (Monopoles, Astrophysics and Cosmic Ray Observatory) detector is presently being installed in the Gran Sasso National Laboratory. It is a large area detector with an acceptance for isotropic particles of about 10.000 m² sr. It is designed to search for rare particles and rare phenomena in the natural penetrating radiation. It will search for GUT Magnetic Monopoles and any supermassive penetrating charged particles; it will perform a survey of cosmic point sources of high energy gammas and neutrinos and a systematic study of cosmic ray muons and multimuons. Three complementary techniques are used: liquid scintillation counters, limited streamer tubes and track-etch. Here we describe the track-etch detector, its implementation for the first supermodule and the tests in progress on CR39 exposed to high energy ions. (author)

[en] The application of track etch detectors in radon and neutron dosimetry is described. Some studies about the neutron dosimetry using CR39 e LR 115 are presented. (E.G.)

[en] Full text: Recently, several researchers have studied about excellent properties of material. Furthermore, Researchers have been issued joining of heterogeneity materials that having different unique properties. Among joining of heterogeneity materials, joining technique of thermoplastics used generally using by low power of diode laser system. And, research to joining of plastic and metal have been studied these days. In existing method of bonding plastic, laser-beam is transmitted to the upper layer and lower layer absorbed laser-beam. And then, the absorbed laser-beam changes the heat energy and it characteristics strong bonding properties. However, when joining of metal and plastic, the joining force is weaker than the joining of plastic and plastic. So, we studied the joining characteristics and enhance adhesion of metal and plastic. First of all, we confirmed that a phenomenon of mutual between plastic and metal transmission joining The material used in the experiment is SUS(SUS316L) and PC(Polycarbonate). PC is thickness 5mm and have transmittance of 91%. SUS is thickness 2mm. Laser source has a wavelength of 1070nm, beam size 10mm, output power 79.57W. And the melting point(about 300℃) of the PC kept by adjustment of processing speed. In order to enhance excellent joining force, we experimented a number of ways such as reducing the gap between the each material, fine patterning surface of the SUS by femtosecond laser, surface texturing. So, the melted PC were tested to more sturdy attach to the joining surface of SUS. (author)