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The unique characteristics of the laser beam compared to the normal light i.e. its directionality, monochromatcity, and brightness make it a very important tool in the surface engineering. The concentrated heat in the laser beam can precisely directed toward the processed region on the surface. The laser beam power, size, and scanning velocity are easily controlled during the different processing methods. Laser surface modifications of metallic materials, such as laser surface melting, laser surface alloying, and laser cladding are some of the most important methods to improve the mechanical properties of the processed layer on the surface. A pulsed Nd-YAG laser surface melted specimens of low carbon steel with a maximum power of 90W at different processing parameters. The rapid melt and resolidification of the treated layer produced a refinement in the microstructure. The original microstructure of this steel (Ferrite + Pearlite) has been transformed to new phases of martensitic and bainitic structures. The melted layer consists of the melted pool, the heat affected zone, and the substrate. The maximum hardness of the laser melted layer is more than 400 HV.

Key words:Laser surface Melting, Carbon steel, Microstructure, Microhardness

الملخص

Dyslexia is a distinct learning disability that is distinguished by difficulties in decoding and reading fluency, spelling as well as other cognitive skills. This research is conducted to assist learning disability by improving the skills required for children with learning disability in reading and spelling using the assistive technology AVA interactive whiteboard. The approach is by strengthening the micro skills required to improve the fundamental skills such as reading, and spelling thus facilitating the learning process. Tactile and visual modalities are the main focus in the use of the interactive whiteboard. This study aims to develop an interactive whiteboard learning prototype for students with dyslexia. A total of six children from 3 demographics (Chinese, Malay, and Indian) participated in the study. Activities improving the four micro skills were introduced in normal whiteboard and the children were exposed to the prototype AVA interactive whiteboard. Responses using Interactive whiteboard were different when compared to their performance with the normal whiteboard. The analyzed results indicated showed improvements in three of the micro skills using IWB

In this paper, deploying an integrator, we propose a method to transform ultra wideband (UWB) signal into a frequency hopping type of transmission signal that is applied in Bluetooth technology. In addition to the tremendous increase in data transfer speed, the frequency domain equalization is further extended to Bluetooth technology, as a result. This paper further shows that both technologies can be deduced from each other although UWB is a carrierless while Bluetooth requires a transmission carrier.

Since the Alhamada area is known for its rangelands and most of its inhabitants raise animals, especially sheep and goats, this study was conducted by collecting samples randomly from six herds of sheep distributed randomly from the specific areas of Qurayat and Ghadames This study was aimed to determine the prevalance of Eimeria, which causes coccidian in sheep's and study the effects of many factors such as age, sex, and the breeding system, it is the first study conducted in the Hamada area on this parasite, using microscopic examination, 54 samples of sheep and goat feces were examined, of different ages and of both sexes in the month of May 2022. The result showed that the infection rate was 28% in sheep and 43% in goats. It was noted that there were no significant differences for age in the infection rate, as the highest infection rate was in the age group (>2) years (39%), while the lowest infection rate was in the age group of (1-2) years (7%), it was also shown that there is no significant difference for gender on the infection rate, as the infection rate in males was (22%) and females (48%). The results showed a slight difference in the infection rate between the open and closed breeding systems in the Hamada region, with the closed system averaging 25% compared to 20% in the open system. Clinical signs also appeared on some of the infected animals, including diarrhea, general weakness, and some of them showed plucking of wool/hair.