The parameters of resistance spot welding (RSW) performed on low strength commercial aluminum sheets are investigated experimentally, the performance requirements and weldability issues were driven the choice of a specific aluminum alloy that was AA1050. RSW aluminum alloys has a major problem of inconsistent quality from weld to weld comparing with welding steel
alloys sheet, due to the higher thermal conductivity, higher thermal expansion, narrow plastic temperature range, and lower electrical resistivity. Much effort has been devoted to the study of describing the relation between the parameters of the process (welding current, welding time, and electrode force) and weld strength. Shear-tensile strength tests were performed to indicate the weld
quality. A weld lobe diagrams were constructed to evaluate the weldability of three sheet thicknesses of this alloy. Most appropriate welding time and electrode force are 5 cycles and 1.75- 2.25 kN respectively. The ranges of the weldability are 14-28, 18-30, and 22-32 kA for 0.6, 1.0, and 1.5 mm sheet thicknesses respectively. A statistical regression analysis was used to demonstrate the
relationship of the process parameters and the strength of the weldments. Two empirical equations for each thickness were proposed to estimate the shear tensile strength of the weldments, one for quadratic and the other linear relationship between the process parameters and the strength. There are no significant differences between the equations when applied to the available data.
Research was: 1- known as self-efficacy when students perceived the university. 2- know the significance of statistical differences in perceived self-efficacy according to gender and specialty. Formed the research sample of (300) students were chosen from the original research community by way of random (150) male specialization and scientific and humanitarian (150) females specialized scientific and humanitarian. The search tool to prepare the yard tool to measure perceived self-efficacy based on measurements and previous literature on the subject of perceived self-efficacy. The researcher using a number of means, statistical, including test Altaúa and analysis of variance of bilateral and results showed the enjoyment of the research s
... Show MoreNahrawan clay deposits lies in Diyala governorate , 65 Km, NE of Baghdad , according to the previous work in this field, in which they study the reserve belong to category of investigation ( C2 & C1 ) , we choice the proper area to investigation of category (B) with drill net( 200x 200m ) to rise the amount of reserve. The investigation work included drilling (116) boreholes of total depth ranges from (10.0-12.55m) , showed mainly clayey and silty deposits with little sand , and the typical borehole (648) represents all types of sediment in the area , and most of boreholes without sandy deposits , and all of these deposits is Quaternary sediment which is consist of two main sedimentary cycles ( the Pleistocene & Holocene ) . Chemical a
... Show MoreThe use of deep learning.
The she/teacher is considered one of the basics of the educational process for its essential role in education and teaching the kindergarten child, thus its lack to construct social relations in side the kindergarten environment working in it regarded one of the shortcoming factors she is suffering from which should be manipulated, because it could effect its enthusiasm to work in the kindergarten according to what has mentioned, the researcher presents the following objective:-
- Identifying level of social enhancement for the kindergarten teachers via the test of the following hypothesis:-
This paper studies the adaptive coded modulation for coded OFDM system using punctured convolutional code, channel estimation, equalization and SNR estimation. The channel estimation based on block type pilot arrangement is performed by sending pilots at every sub carrier and using this estimation for a specific number of following symbols. Signal to noise ratio is estimated at receiver and then transmitted to the transmitter through feedback channel ,the transmitter according to the estimated SNR select appropriate modulation scheme and coding rate which maintain constant bit error rate
lower than the requested BER. Simulation results show that better performance is confirmed for target bit error rate (BER) of (10-3) as compared to c
Abstract
In this research we study the wavelet characteristics for the important time series known as Sunspot, on the aim of verifying the periodogram that other researchers had reached by the spectral transform, and noticing the variation in the period length on one side and the shifting on another.
A continuous wavelet analysis is done for this series and the periodogram in it is marked primarily. for more accuracy, the series is partitioned to its the approximate and the details components to five levels, filtering these components by using fixed threshold on one time and independent threshold on another, finding the noise series which represents the difference between
... Show MoreIn the current study, a novel approach for separating ethanol-water mixture by microbubble distillation technology was investigated. Traditional distillation processes require large amounts of energy to raise the liquid to its boiling point to effect removal of volatile components. The concept of microbubble distillation by comparison is to heat the gas phase rather than the liquid phase to achieve separation. The removal of ethanol from the thermally sensitive fermentation broths was taken as a case of study. Consequently the results were then compared with those which could be obtained under equilibrium conditions expected in an “ideal” distillation unit. Microbubble distillation has achieved vapour compositions higher than th
... Show MoreThe levels of shooting in basketball not very good appears un healthy phenomenon for age stages especially youth players on Iraq and therefore there is lower level in skills especially shooting that seems the players represent their players not good levels which cause difficult in choosing players for youth national team. The research sample were youth teams in Baghdad for season 2012-2013 their birth 1996 and the number teams (7) and after getting results and treat it statically the important ones were : there is a large number of failure attempts on success ones in basic shooting in basketball for youth teams in Baghdad teams (2012-2013) season and basic shooting have effective participation (positive relation) in youth teams ranking in B
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