Abstract-A biconical antenna has been developed for ultrawideband sensing. A wide impedance bandwidth of around 115% at bandwidth 3.73-14 GHz is achieved which shows that the proposed antenna exhibits a fairly sensitive sensor for microwave medical imaging applications. The sensor and instrumentation is used together with an improved version of delay and sum image reconstruction algorithm on both fatty and glandular breast phantoms. The relatively new imaging set-up provides robust reconstruction of complex permittivity profiles especially in glandular phantoms, producing results that are well matched to the geometries and composition of the tissues. Respectively, the signal-to-clutter and the signal-to-mean ratios of the improved method are consistently higher than 5 dB and 10 dB, corresponding to an average increase in image fidelity of more than 140% compared to conventional radar focusing technique.
The matter of handwritten text recognition is as yet a major challenge to mainstream researchers. A few ways deal with this challenge have been endeavored in the most recent years, for the most part concentrating on the English pre-printed or handwritten characters space. Consequently, the need to effort a research concerning to Arabic texts handwritten recognition. The Arabic handwriting presents unique technical difficulties because it is cursive, right to left in writing and the letters convert its shapes and structures when it is putted at initial, middle, isolation or at the end of words. In this study, the Arabic text recognition is developed and designed to recognize image of Arabic text/characters. The proposed model gets a single line of Arabic text, which convert and segments into words and then segments into letters. A multilayer feed forward neural network is trained to recognize these segments as characters. The final results indicate and clarify that the proposed system perform an effective accuracy of recognition rated up to 83% for Arabic text.
Aims: To evaluate the effect of repair techniques, surface treatment with monomer, and additional curing cycle on the color change, and residual monomer of the repaired denture base. Materials and methods: Two hundred and seventy two samples of two brands heat cured acrylic resin were repaired by four different techniques (water bath, microwave, thermo press, and chemically cured acrylic resin), treated, and untreated with monomer, and repaired with 3 mm space at fracture area. The samples were tested to measure color change and residual monomer of repaired, and intact (control) samples. Results: Color change of acrylic denture base repaired by chemically cured acrylic resin was significantly higher than that of water bath, microwave, and thermo press. Microwave repairing technique had lower residual monomer than other techniques. The highest content of residual monomer was released in water after the first 24 hours and decreased in the subsequent days. Acrylic denture base that has additional curing cycle showed a residual monomer content lower than those with single curing cycle. Conclusion: Color changes of repaired denture with chemically cured resin are high and the lower adverse effect of monomer are shown with microwave and water bath curing cycle. Long storage period of repaired denture base are beneficial to reduce monomer release.
Aims: to evaluate the some physical properties (melting range, hardness and thermal expansion) of two prepared mixtures wax contain paraffin oil in comparison with commercial type wax. Materials and Methods: Two mixtures of experimental modeling wax were prepared, mixture No.1 (M1) and mixture No.2 (M2). These two mixtures underwent three physical tests in compare to commercial modeling wax which is a control group, these tests are: 1-Melting range test, 5 capillary tubes were sealed and filled with all type of wax and placed inside electro thermal melting point apparatus.The start of melting wax considered the beginning melting point and when the wax completely became fluid, it is considered the ending melting point. 2 Needle penetration test (hardness test), 5 cylindrical shape samples for each type of wax were prepared and tested for hardness by standard vicate apparatus. 3-Linear thermal expansion, for each type of wax, 5 samples were prepared in a mold , the samples were heated to 25 C° and 40 C° and the distance between reference marks at the lower temperature and the change in length on heating to higher temperature is determined by electronic digital caliper and thermal expansion is calculated as percentage of the total length of sample. Results: Statistical analysis of melting range test showed a significant difference between tested groups in both minimum and maximum melting point. M1 had the higher mean in minimum and maximum melting point. Hardness test analysis showed a significant difference between tested groups, higher mean of hardness was observed in M2, M1 and control group respectively. ANOVA of linear thermal expansion showed a significant difference between groups at 25 C° and at 40 C°. The control group of wax observed the highest mean of thermal expansion at 25 C° and 40 C° than the other two types of wax.Conclusion: The modification of dental wax improved some of the physical properties than commercial one.
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