Unlike welding, soldering does not involve melting the work pieces. Soldering is a process in which two or more items are joined together by melting and putting a filler metal (solder) into the joint. Failure in the solder joint may make the system components lose their functions. Electrical wiring and electronic components are joined to devices and printed circuit boards using soldering. Soldering and brazing are both used in the assembly of musical instruments. Lead-tin alloy solder employed in the current investigation which has a diameter of 4 mm and a density of 11.0103 kg/m3 with continuous heat flux heating from the domain's left side and complete insulation on the other side. The melting of PCM was simulated using the ANSYS (Fluent) melting model. Three procedures were followed during the heating stage of the reflow process to perform the melting heat-transfer analysis. The simulation's results were recorded at regular intervals of 15 seconds. The results show melting rate increases as time proceeds. It is almost the same at the initial stages and increases in the middle and the end of the melting process. Heat transfer happens mostly through conduction during the first 0–30 seconds of the melting process, changing to natural convection as the material continues to heat up.
The research problem has crystallized and in light of these capabilities, the level of performance depends on the application of modern training methods based on actual experimentation, and those methods aim to develop the components of achievement in this competition, including the quantities of exerting the distinctive strength with speed for the arms and feet, which reflects on good skillful performance because the skill of shooting by jumping forward and high forms A major role in achieving goals during the competition that qualifies the team to win, and through the follow-up of the researcher in the field and academic field, I noticed that there is a weakness in some physical abilities, which affects performance and skill level
... Show MoreThe study aims at studying and analyzing the subject of marketing vigilance as it is one of the modern approaches in the marketing field that can be used to face changes in the competitive and strategic environment and that represents quick reactions on the part of the institution to ensure its survival and distinctiveness other aims are: Consolidating the strength of the marketing organization and its success continuously, represented by changes in the market share, awareness of the institution's position in the market and its relations with competing tourism companies, diversification of tourism services, as well as an analysis of the competitive strategic position of tourism institutions for the purpose of conducting a r
... Show MoreHistorically, medicinal herbs have been utilized as an important origin of chemicals with particular therapeutic potentials, and they continue to be a great place to find new medication candidates. Parthenocissus quinquefolia L. is a member of the grape-growing family Vitaceae. It is indigenous to Central and North America. It is widely dispersed in Iraqi gardens and plant houses from north to south. Traditionally, it has many uses, like relieving constipation, treating jaundice, expectorant, emetic, and others. At the same time, its proven activities include antioxidant activity, antimicrobial, anti-diabetic, thrombin inhibitor effect, and medicine for treating eyelid eczema. Parthenocissus quinquefolia contains valuable phytochemicals lik
... Show MoreMaintaining the quality of apricot fruits during storage is not an easy task due to the changes in their physical and chemical properties, so it is necessary to use less expensive, easy to apply, environmentally friendly, and safer preservatives to maintain the nutritional value of apricot. The damage to some fruits during storage can be a source of infection, which leads to the damage of healthy fruits more quickly, which requires building an intelligent model to detect damaged fruits. The aim of the research is to study the effect of immersing apricots in lemon juice once and sugar-water solution again on the quality properties of apricots, including sweetness, color, hardness, and water content. On the other hand, the YOLOv7 algorithm wa
... Show MoreAbstract
The government spending in Iraq and witnessed the changes and developments, especially after 2003, which outweighed consumer spending at the expense of capital expenditure and increased support and diversity of trends towards improving pension conditions for member
... Show MoreIn this article, a new deterministic primality test for Mersenne primes is presented. It also includes a comparative study between well-known primality tests in order to identify the best test. Moreover, new modifications are suggested in order to eliminate pseudoprimes. The study covers random primes such as Mersenne primes and Proth primes. Finally, these tests are arranged from the best to the worst according to strength, speed, and effectiveness based on the results obtained through programs prepared and operated by Mathematica, and the results are presented through tables and graphs.
The current research aims to determine the impact of the cognitive reconstruction program on the development of psychological hardness among middle school students through the experimental verification of three hypotheses. The research sample consisted of (16) out of (450) students selected from Ibn Rushud preparatory school- Al-Rusafa 2. These participants have been randomly distributed into two equal groups. The researcher has used the method of cognitive reconstruction with the experimental group, whereas with the controlling group, he used nothing. The researcher has further used the scale of psychological hardness of Kobassa with the participants; the scale has been built in a way that suits the sample of the study, which consisted
... Show MoreDiabetes mellitus is a metabolic chronic disease, with global estimation increase in patient (around 100 million in 2030).The aim of the current study is to investigate vitamin D, C-reactive protein and estradiol levels in pre and postmenopausal Iraqi women with type 2 diabetes (T2MD).A total of 176 female distributed into two groups: the first included 90 women withT2MD (43 pre and 47 post-menopausal); the second group included 86 healthy subjects (41 pre and 45 postmenopausal) considered as control. This study has shown that women in premenopausal (20-40 years) had highly significant difference in the estradiol and vitamin D levels in diabetes subjects (62.192 ± 17.643pg/ml, 10.522 ± 1.958ng/ml) compared with healthy (131.793 ± 1
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This paper describes DC motor speed control based on optimal Linear Quadratic Regulator (LQR) technique. Controller's objective is to maintain the speed of rotation of the motor shaft with a particular step response.The controller is modeled in MATLAB environment, the simulation results show that the proposed controller gives better performance and less settling time when compared with the traditional PID controller.