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Drilling of FR-4 Composite Materials Using Single Pulse of Nd:YAG Laser
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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.  

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Publication Date
Mon Aug 01 2022
Journal Name
Baghdad Science Journal
The Effect of White Rot Fungus (Ganoderma sp) as Decomposers on Composting Using Combination of Cattle Feces and Water Hyacinth (Eichhornia crassipes) as Organic Matter
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In Indonesia, cattle feces (CF) and water hyacinth (WH) plants are abundant but have not been widely revealed. The use of microorganisms as decomposers in the fermentation process has not been widely applied, so researchers are interested in studying further. This study was to evaluate the effect of the combination of CF with WH on composting by applying white-rot fungal (WRF) (Ganoderma sp) microorganism as a decomposer. A number of six types of treatment compared to R1(ratio of CF:WH)(25%:75%)+WRF; R2(ratio of CF:WH)(50%:50%)+WRF; R3(ratio of CF:WH)(75%:25%)+WRF; R4(ratio of CF:WH)(25%:75%) without WRF; R5(ratio of CF:WH)(50%:50%) without WRF; R6(ratio of CF:WH)

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Publication Date
Sun Mar 01 2015
Journal Name
Journal Of Engineering
Finite Element Investigation on Shear Lag in Composite Concrete-Steel Beams with Web Openings
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In this paper, effective slab width for the composite beams is investigated with special emphasis on the effect of web openings. A three dimensional finite element analysis, by using finite element code ANSYS, is employed to investigate shear lag phenomenon and the resulting effective slab width adopted in the classical T-beam approach. According to case studies and comparison with limitations and rules stipulated by different standards and codes of practice it is found that web openings presence and panel proportion are the most critical factors affecting effective slab width, whereas concrete slab thickness and steel beam depth are less significant. The presence of web opening reduces effective slab width by about 21%.

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Publication Date
Sat Dec 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Compare Estimate Methods of Parameter to Scheffʼe Mixture Model By Using Generalized Inverse and The Stepwise Regression procedure for Treatment Multicollinearity Problem
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Mixture experiments are response variables based on the proportions of component for this mixture. In our research we will compare the scheffʼe model with the kronecker model for the mixture experiments, especially when the experimental area is restricted.

     Because of the experience of the mixture of high correlation problem and the problem of multicollinearity between the explanatory variables, which has an effect on the calculation of the Fisher information matrix of the regression model.

     to estimate the parameters of the mixture model, we used the (generalized inverse ) And the Stepwise Regression procedure

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Publication Date
Fri Dec 15 2023
Journal Name
Iraqi Journal Of Laser
In vitro Investigation the Antifungal and 940 nm Diode Laser Effects on Inhibition of Candida Albicans Isolated from Oral Cavity
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Background: Candida albicans is a prevalent commensal that can cause severe health problems in humans. One such condition that frequently returns after treatment is oral candidiasis. Aim: the goal of this research is to evaluate the efficiency of 940 nm as a fungicidal on the growth of Candida albicans in vitro. Material and Methods: In vitro samples (fungal swabs) were taken from the oral cavity of 75 patients suffering from oral thrush. Following the process of isolating and identifying Albicans. The samples are divided into four groups:(Group 1): Suspension of C. albicans was put in a solution of saline as a control group. (Group 2): Suspension of C. albicans that had been treated wit

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Publication Date
Sun Jul 09 2023
Journal Name
Journal Of Engineering
The Effective Width in Composite Steel Concrete Beams at Ultimate Loads
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A composite section is made up of a concrete slab attached to a steel beam by means of shear connectors. Under positive and negative bending moment, part of the slab will act as a flange of the beam, resisting the longitudinal compression or tension force. When the spacing between girders becomes large, it is evident that the simple beam theory does not strictly apply because the longitudinal stress in the flange will vary with distance from the girder web, the flange being more highly stressed over the web than in the extremities. This phenomenon is termed "shear lag". In this paper, a nonlinear three-dimensional finite element analysis is employed to evaluate and determine the actual effective slab width of the composite steel-concrete

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Publication Date
Wed Jul 20 2022
Journal Name
Journal Of Materials Engineering And Performance
High Speed Shock Peening by Fiber Laser for Al Alloy 6061-T6 Thin Sheets
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Under cyclic loading, aluminum alloys exhibit less fatigue life than steel alloys of similar strength and this is considered as Achilles's heel of such alloys. A nanosecond fiber laser was used to apply high speed laser shock peening process on thin aluminum plates in order to enhance the fatigue life by introducing compressive residual stresses. The effect of three working parameters namely the pulse repetition rate (PRR), spot size (ω) and scanning speed (v) on limiting the fatigue failure was investigated. The optimum results, represented by the longer fatigue life, were at PRR of 22.5 kHz, ω of 0.04 mm and at both v's of 200 and 500 mm/sec. The research yielded significant results represented by a maximum percentage increase in the fa

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Publication Date
Tue Dec 31 2013
Journal Name
مجلة كليه التربيه الاساسيه
صعوبات تدريس مادة الكيمياء الكمية في قسم الكيمياء - كلية التربية - للعلوم الصرفة من وجهة نظر تدريسي المادة و الطلبة
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تعد أساليب وطرائق تدريس المواد الدراسية العلمية من المجالات المهمة التي تساعد في تحويل المجرد إلى ثوابت في الذهن وترفع مستوى خبرات كل من المعلم والمتعلم على حد سواء إضافة إلى إنها جزء لا يتجزأ من العملية التربوية ومن الركائز المهمة التي تقوم عليها المناهج الدراسية لأنها تساعد الطلبة على اكتساب مهارات ومعلومات وتكوين اتجاهات وميول تخدم أهداف تدريس المادة وبما أن مادة الكيمياء الكمية هي إحدى المواد الدراسية

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Publication Date
Sat Nov 01 2014
Journal Name
International Journal Of Statistics
Single and Double Stage Shrinkage Estimators for the Normal Mean with the Variance Cases
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Publication Date
Sat Mar 01 2025
Journal Name
Acta Marisiensis - Seria Medica
Transcatheter balloon valvuloplasty for children with severe pulmonary valve stenosis: A single-center experience
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Abstract<p> <bold>Objectives</bold>: this study aim to assess the effectiveness of the Transcatheter balloon valvoplasty (BVP) of severe Pulmonary stenosis (PS) and identify possible complications and predictors for the outcome.</p><p> <bold>Methods</bold>: A retrospective study was conducted at the Iraqi Center of Cardiac Diseases for a 2-year duration in the period from 2021 to the end of 2023; the patients with confirmed severe PS of both genders within the age equal to or less than 18 years were included. For every patient included in the present study, the following data were collected: Demographic data, Echoc</p> ... Show More
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Publication Date
Wed Jan 01 2014
Journal Name
International Journal Of Computer Applications
Enhancing the Delta Training Rule for a Single Layer Feedforward Heteroassociative Memory Neural Network
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In this paper, an algorithm is suggested to train a single layer feedforward neural network to function as a heteroassociative memory. This algorithm enhances the ability of the memory to recall the stored patterns when partially described noisy inputs patterns are presented. The algorithm relies on adapting the standard delta rule by introducing new terms, first order term and second order term to it. Results show that the heteroassociative neural network trained with this algorithm perfectly recalls the desired stored pattern when 1.6% and 3.2% special partially described noisy inputs patterns are presented.