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.
This paper focuses on the optimization of drilling parameters by utilizing “Taguchi method” to obtain the minimum surface roughness. Nine drilling experiments were performed on Al 5050 alloy using high speed steel twist drills. Three drilling parameters (feed rates, cutting speeds, and cutting tools) were used as control factors, and L9 (33) “orthogonal array” was specified for the experimental trials. Signal to Noise (S/N) Ratio and “Analysis of Variance” (ANOVA) were utilized to set the optimum control factors which minimized the surface roughness. The results were tested with the aid of statistical software package MINITAB-17. After the experimental trails, the tool diameter was found as the most important facto
... Show MoreThe purpose of this study is to examine the moderating role of business environment on the relationship between Entrepreneurial Skills (ES) and business performance of Small Business (SB) in Iraq, Baghdad. This study aims to resolve the inconsistencies found in the contemporary literature regarding the relationship between ES and business performance. Questionnaire using a 5-point Likert scale was adopted from previous work to ascertain the responses of the respondents. Survey research design was adopted, and self-administered questionnaires were used to collect the data from small business owners in 9 districts in Baghdad the capital of Iraq. The analysis was conducted using SPSS version 23.0. The direct relationship and hierarchical regre
... Show MoreLimited importance of research in a stand on the most important difficulties faced by both faculty and parents to communicate with each process to follow up on their children, and the analysis and inventory of the obstacles that hinder the educational process, and work to develop a vision of how to address these constraints and the important role of technology in the treatment of problems of the society so as to develop frameworks future to minimize the errors and the problems they face, and the development outlook for future generations in order to promote the educational level, especially that Iraq is going through a change in conditions in all sectors. Through the questionnaire, which includes questions set that was made on a sample o
... Show MoreAbstract
Experimental work from Magnetic Abrasive Finishing (MAF) tests was carried out design parameters (amplitude, and number of cycle which are formed the shape of electromagnetic pole), and technological parameters (current, cutting speed, working gap, and finishing time) all have an influence on the mechanical properties of the surface layer in MAF process. This research has made to study the effect of design and technological parameters on the surface roughness (Ra), micro hardness (Hv) and material removal (MR) in working zone. A set of experimental tests has been planned using response surface methodology according to Taguchi matrix (36) with three levels and six factors
... Show MoreIn this study, the energy charging mechanism is mathematically modeled to determine the impact of design modifications on the thermofluidic behavior of a phase change material (PCM) filled in a triplex tube containment geometry. The surface area of the middle tube, where the PCM is placed, is supported by single or multi-internal frustum tubes in vertical triplex tubes to increase the performance of the heating and cooling of the system. In addition to the ordinary straight triplex tubes, three more scenarios are considered: (1) changing the middle tube to the frustum tube, (2) changing the inner tube to the frustum tube, and (3) changing both the internal and central tubes to the frustum tubes. The impact of adopting the tube desig
... Show MoreBurdock ( Arctium lappa), is among the most popular plants in traditional medicine and it is associated with several biological effects. Literature survey revealed the presence of phenylpropanoid compounds .The most widespread are hydroxycinnamic acids ( mainly caffeic acid and chlorogenic acid) and lignans (mainly arctiin and arctigenin). This work will confirm the presence of these compounds in Arctium lappa, cultivated in Iraq, in both root and leaf samples. The dried plant samples were extracted by soxhlet with 80% methanol then separated the main constituents by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Identification of the isolated compounds wa
... Show MoreThe aim of this paper is to investigate the effects of Nd:YAG laser shock processing (LSP) on micro-hardness and surface roughness of 86400Cu-Zn alloy. X-ray fluorescence technique was used to analyze the chemical composition of this alloy. LSP treatment was performed with a Q-switched Nd: YAG laser with a wavelength of 1064 nm. The results show that laser shock processing can significantly increase. The micro-hardness and surface roughness of the LSP-treated sample. Vickers diamond indenter was used to measure the micro-hardness of all samples with different laser pulse energy and the different number of laser pulses. It is found that the metal hardness can be significantly increased to more than 80% by increasing the laser energy and t
... Show MoreThe research aims to identify small and medium enterprises in accounting thought in terms of definition and concept, and this international financial reporting standard for small and medium-sized enterprises (SMEs) in the theoretical aspect. As for the practical aspect, the small and medium-sized enterprises standard has been applied to the financial statements of the company in question, the preparation of the opening entry on the date of the transition, the requirements of measurement and the accounting disclosure on the date following the application of the standard, and the preparation of the company's financial statements and the accompanying explanations according to the standard of small and medium-sized enterprises. The r
... Show MoreThe rheological behavior among factors that are present in Stokes law can be used to control the stability of the colloidal dispersion system. The felodipine lipid polymer hybrid nanocarriers (LPHNs) is an interesting colloidal dispersion system that is used for rheological characteristic analysis. The LPHNs compose of polymeric components and lipids. This research aims to prepare oral felodipine LPHNs to investigate the effect of independent variables on the rheological behavior of the nanosystem. The microwave-based technique was used to prepare felodipine LPHNs (H1-H9) successfully. All the formulations enter the characterization process for particle size and PDI to ascertain the colloidal properties of the prepared nanosystem t
... Show MoreTetragonal compound CuAl0.4Ti0.6Se2 semiconductor has been prepared by
melting the elementary elements of high purity in evacuated quartz tube under low
pressure 10-2 mbar and temperature 1100 oC about 24 hr. Single crystal has been
growth from this compound using slowly cooled average between (1-2) C/hr , also
thin films have been prepared using thermal evaporation technique and vacuum 10-6
mbar at room temperature .The structural properties have been studied for the powder
of compound of CuAl0.4Ti0.6Se2u using X-ray diffraction (XRD) . The structure of the
compound showed chalcopyrite structure with unite cell of right tetragonal and
dimensions of a=11.1776 Ao ,c=5.5888 Ao .The structure of thin films showed