Porous Silicon (PS) layer has been prepared from p-type silicon by electrochemical etching method. The morphology properties of PS samples that prepared with different current density has been study using atom force measurement (AFM) and it show that the Layer of pore has sponge like stricture and the average pore diameter of PS layer increase with etching current density increase .The x-ray diffraction (XRD) pattern indicated the nanocrystaline of the sample. Reflectivity of the sample surface is decrease when etching current density increases because of porosity increase on surface of sample. The photolumenses (PL) intensity increase with increase etching current density. The PL is affected by relative humidity (RH) level so we can use as humidity sensor. The electrical resistivity has been increased after PS layer formed due to the variation of the pore size and it was much higher after increase etching current.
Prosthetic hands are compensatory devices for the hand amputees as a result of injury, various accidents or birth deformities, types of prosthetic hand vary depending on the mechanism they operate and how they perform. There are common types in use that are characterized by their complex mechanisms, which are difficult for the amputee to use or exclude use because of their high cost, therefore the aim of this research is to design an artificial hand that is suitable in terms of simplicity of use and low cost and similar to a natural hand with regard to dimensions and shape that operated in the mechanism of links. This research involves Stress and strain analysis of the prosthetic hand and its fingers that modelled from (Petg CR)
... Show MoreThe current study included a review of the registration and description of the Theretra alecto Boi, 1827 (Levant hawk moth), samples were collected from various areas of the Baghdad belt and the provinces of the Middle Euphrates, confirmation in the description was on the most important parts of the body included the head and it's appendages, pronotum, wings as well as male and female genitalia. The morphological characteristics under study were enhanced by illustrations and images. Information on the locations and date of the collection was also confirmed. This study aims to identify the most important characteristics of the diagnosis of the species and the review of appearance variations, especially the analytical style of wings, coupling
... Show MoreEnrollment in kindergarten child accomplishes many positive aspects, that’s what Im sure a lot of modern educational trends in child education preschool in the importance of exposing children to a variety of sensory stimuli that contribute to impart a range of sound concepts.
Current research aims to know:
1.the level of sensory perception in the first primary grade students a sample search.
2.differences in perception of elementary first-graders with variable gender male, female)) 3.differences in perception of the first primary grade students attending and not attending kindergarten in accordance with variable attendance (attending, not attending).
school students (first grade) from attendi
... Show MoreGas hydrate formation is considered one of the major problems facing the oil and gas industry as it poses a significant threat to the production, transportation and processing of natural gas. These solid structures can nucleate and agglomerate gradually so that a large cluster of hydrate is formed, which can clog flow lines, chokes, valves, and other production facilities. Thus, an accurate predictive model is necessary for designing natural gas production systems at safe operating conditions and mitigating the issues induced by the formation of hydrates. In this context, a thermodynamic model for gas hydrate equilibrium conditions and cage occupancies of N2 + CH4 and N2 + CO4 gas mix
Data <span>transmission in orthogonal frequency division multiplexing (OFDM) system needs source and channel coding, the transmitted data suffers from the bad effect of large peak to average power ratio (PAPR). Source code and channel codes can be joined using different joined codes. Variable length error correcting code (VLEC) is one of these joined codes. VLEC is used in mat lab simulation for image transmission in OFDM system, different VLEC code length is used and compared to find that the PAPR decreased with increasing the code length. Several techniques are used and compared for PAPR reduction. The PAPR of OFDM signal is measured for image coding with VLEC and compared with image coded by Huffman source coding and Bose-
... Show MoreThe digital camera which contain light unit inside it is useful with low illumination but not for high. For different intensity; the quality of the image will not stay good but it will have dark or low intensity so we can not change the contrast and the intensity in order to increase the losses information in the bright and the dark regions. . In this search we study the regular illumination on the images using the tungsten light by changing the intensities. The result appears that the tungsten light gives nearly far intensity for the three color bands(RGB) and the illuminated band(L).the result depend on the statistical properties which represented by the voltage ,power and intensities and the effect of this parameter on the digital
... Show MoreIn this paper, a design of the broadband thin metamaterial absorber (MMA) is presented. Compared with the previously reported metamaterial absorbers, the proposed structure provides a wide bandwidth with a compatible overall size. The designed absorber consists of a combination of octagon disk and split octagon resonator to provide a wide bandwidth over the Ku and K bands' frequency range. Cheap FR-4 material is chosen to be a substate of the proposed absorber with 1.6 thicknesses and 6.5×6.5 overall unit cell size. CST Studio Suite was used for the simulation of the proposed absorber. The proposed absorber provides a wide absorption bandwidth of 14.4 GHz over a frequency range of 12.8-27.5 GHz with more than %90 absorp
... Show MoreAbstract:
The current research aims to distinguish the talent for the kindergarten
children and its relation with some changes . The research included ( 170 )
child (male , female ) from the kindergarten children on the year 2009 – 2010
the researcher had used PRED meter to achieve the goals of this research
after being sure from the honesty and the prove and the ( person ) connection
coefficient had been used to discover the relation between the talent and the
changes which had been mentioned in the research . The result proved that
the children had talents the toys and the educational scientifically scholarship
finally the researcher had presented some recommendations and suggestions
for other studies .<