Sar Sardy

Preliminary analysis of C and H in a Sangiran fossil using laser-induced plasma at reduced pressure

A Nd:YAG laser (1064nm, 120mJ, and 8ns) was focused on various types of fossil samples, including fossilized buffalo horns (around 400 000 and 1×106yr old, respectively) found in Sangiran, Indonesia. Such fossils represent an important starting point for tracing man’s origin and evolution during the Pleistocene era. Carbon emission was found to decrease significantly with the degree of fossilization and no carbon emission was found in a horn fossil dated at 1×106yr. Some molecular band spectra were also found in all the fossils examined in this study. It was assumed that by combining information on carbon emission, hydrogen emission, and molecular band spectra that the degree of fossilization might be quantitatively calculated. Further results showed that silicon emission is not detected in old fossils, but it is present as a major constituent. This is probably due to the fact that silicon is strongly bound to other elements in old fossils and is ablated in the form of clusters. In order to prove the abov...

Experimental medical and industrial applications of neural networks to image inspection using an inexpensive personal computer

We demonstrate experimentally the application of adaptive resonance theory (ART2) to disease identification from mammographic images, and the application of Kohonens self-organizing map and multilayer perceptron to textile defect detection using an inexpensive personal computer.

Plasma emission induced by an Nd-YAG laser at low pressure on solid organic sample, its mechanism, and analytical application

An Nd-YAG laser (1064 nm, 120 mJ, 8 ns) was focused on various types of solid organic samples such as a black acrylic plate, a black polyvinyl chloride plastic sheet, and a methoxy polyaniline film coated on the surface of a glass substrate, under a surrounding air pressure of 2 Torr. A modulated plasma technique was used to study the mechanism of excitation of the emission of the organic material. As a result, we conclude that ablated atoms and molecules are excited by a shock-wave mechanism, similar to the case of hard samples such as metal. The ablation speed of hydrogen emission (H I 656.2 nm) was examined and the results show that the release speed of the ablated atoms is relatively low (less than Mach 10) and persists for a longer period of time (around 1 μs); this phenomenon can be understood by assuming that the soft target absorbs recoil energy, causing a low release speed of ablated atoms which would form the shock wave. This was overcome by placing a subtarget on the back of the soft sample so ...

Determination of adaptive quantization factors in coding-decoding process of JPEG2000 by using fuzzy logic

The JPEG2000 is new image compression standard, which develop different quantization factors in each sub-band of the wavelet transform, where those factors are attached in image format. In this paper, we develop an algorithm to determine those factors adaptively by using fuzzy logic, therefore it will became more suitable to each image condition, and also provides an effective and better compression ratio. The available low and high frequency image samples are used, and the criteria of output results such as: Peak Signal to Noise Ratio (PSNR), Compression Ratio (CR), Entropy, etc., will be compared. The simulation results indicate that such algorithm can improve image quality as well as the compression performance accordingly.