Laser drilling is capable of producing small, precisely positioned holes with high degree of reproductively. In this paper , IR millisecond Nd:YAG single pulsed laser was used to determine the effect of laser parameters on the drilled hole of the glass - fiber reinforced epoxy composite FR-4 sample of 2 mm in thickness . The type of laser source was GSI lumonics JK760TR Series laser 1.064μm system in a CNC cabin. The JK760TR series has a 0.3-50ms pulse length and a maximum repetition rate 500Hz with an average power of 600W. The investigation of single pulse laser drilling in this paper was based on theoretical and experimental solutions. In single pulse technique, the investigation included focal plane position fpp, pulse shape, laser peak power, and pulse duration. It was found that (-1) was the best fpp due to less taper for the drilled holes made by this level (Entrance hole =0.68, Exit hole = 0.27). To predict pulse shape effects; three types were : rectangular , rump-up and cool down, it were examined found that rectangular pulse was efficient more than the other types due to its ability to produce holes with less tapering as compared with others types. Also its found that all pulse shapes had the same effect on the materials microstructure . Laser peak power and pulse duration had the predominant affects on the hole dimensions and edge quality without any defect except hole tapering.
The study aims to identify the effectiveness of a structural theory-based training program in enhancing the teaching practices of Arabic language teachers teaching grade ten in South Al Batinah in Sultanate of Oman. The study used the quasi-experimental design, and the sample consisted of 40 male and female teachers. To achieve the objectives of the study, a training program, an observation form and a measurement tool of teachers’ tendencies towards a structural teaching were made. The program was implemented with an experimental group of 20 female and male teachers in the first semester of the academic year 2018/2019. The study has found that there is a statistically significant difference between the average grades before and after i
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The rehabilitation of deteriorated pavements using Asphalt Concrete (AC) overlays consistently confronts the reflection cracking challenge, where inherent cracks and joints from an existing pavement layer are mirrored in the new overlay. To address this issue, the current study evaluates the effectiveness of Engineered Cementitious Composite (ECC) and geotextile fabric as mitigation strategies. ECC, characterized by its tensile ductility, fracture resistance, and high deformation capacity, was examined in interlayer thicknesses of 7, 12, and 17 mm. Additionally, the impact of geotextile fabric positioning at the base and at 1/3 depth of the AC specimen was explored. Utilizing the Overlay Testing Machine (OTM) for evaluations, the research d
... Show MoreEl estudio se clasifica dentro los estudios teóricos sobre literatura que se ocupa del estudio de los métodos de la crítica literaria: El Estructralismo literario francés y el Formalismo ruso del siglo XX que se utilizan en la interpretación literaría. Las dos corrientes literarias estudian la literatura como ciencia que busca aplicar un método científico al estudio de la literatura. Dicho estudio trata de exponer las teorías críticas que surgen en el debate de la interpretación de los textos literarios como el de Susan Sontag, Ricoeur Paul y Mijail Bajitin, etc. Además se incluye algunos ejemplos implican el análisis estructuralista y formalista como Kafka y la tragedia Judía. y Sur Racine.
ABSTRACT:
... Show MoreLas diferencias entre el pretérito perfecto simple y el imperfecto son uno de los temas más complejos de la lengua española, no sólo para el estudiante, sino para el profesor, puesto que sistematizar los casos y hacerlos fácilmente comprensibles al alumno es tarea difícil. Los profesores de lengua, cuyas investigaciones han dado lugar a una serie de teorías y de corrientes metodológicas y didácticas que permiten enfocar la enseñanza de una lengua extranjera de manera muy distinta a como se hacía tradicionalmente. Vamos a repasar muy brevemente cuáles son estas teorías.
En primer lugar es necesario señalar en qué consiste el aprendizaje de una segunda lengua:
"El aprendizaje de una segunda lengua (L2) es el
... Show MoreThe eaction of 2 4 .6-trihydroxyactophenonemonohydra1e with
l hydr.azine monohydrate was realized ti·nder reflu.(( in methanol and i:l.
Jew drops of glacial acetic acid we.re added to give lhe'(int rmediate)
2-(1hydr pno-ctbyt)-benzcne-·1.3.5-r:Qql, which reacted wittl
saEcy.laldehyde. jn methm)ql to gjy;e 'a new :tyRe CNzOi) Ligand (H:flL]
f(2-{1-[(2-=bydroxy-bertzylide·ne)-bydrazqoo,J-e·thy.1}bcnze·neJ ;3·,5
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New Schiff base [3-(3-acetylthioureido)pyrazine-2-carboxylic acid][L] has been prepared through 2 stages, the chloro acetyl chloride has been reacting with the ammonium thiocyanate in the initial phase for producing precursor [A], after that [A] has been reacting with the 3-amino pyrazine-2-carboxilic acid to provide a novel bidentate ligand [L], such ligand [L] has been reacting with certain metal ions in the Mn(II), VO(II), Ni(II), Co(II), Zn(II), Cu(II), Hg(II), and Cd(II) for providing series of new metal complexes regarding general molecular formula [M(L)2XY], in which; VO(II); X=SO4,Y=0, Co(II), Mn(II), Cu(II), Ni(II), Cd(II), Zn(II), and Hg(II); Y=Cl, X=Cl. Also, all the compounds were characterized through spectroscopic techniques [
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Innovative various Schiff bases and their Co(II), Ni(II) and Cu(II) and Hg(II) compounds made by the condensation of 4-amino antipyrine with derived aminobenzoic acid (2-aminobenzoic acid, 3-aminobenzoic acid, and 4-aminobenzoic acid ) have been prepared by conventional approaches. These complexes were described by magnetic sensibility analysis, FT-IR spectra, and molar-conductance and elemental analysis. Analytical values appeared which the mixed-ligand complexes presented ratio about 2:1 (ligand: metal) with the chelation 4 or 6. The prepared compounds offered a good effect on the organisms; bacteria Staphylococcus-aurous, Escherichia-coli and fungi C. albicans, A. niger. Also, the biological products signalize which the mixed compl
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Compression is the reduction in size of data in order to save space or transmission time. For data transmission, compression can be performed on just the data content or on the entire transmission unit (including header data) depending on a number of factors. In this study, we considered the application of an audio compression method by using text coding where audio compression represented via convert audio file to text file for reducing the time to data transfer by communication channel. Approach: we proposed two coding methods are applied to optimizing the solution by using CFG. Results: we test our application by using 4-bit coding algorithm the results of this method show not satisfy then we proposed a new approach to compress audio fil
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