The current study examined the effect of different sample sizes to detect the Item differential functioning (DIF). The study has used three different sizes of the samples (300, 500, 1000), as well as to test a component of twenty polytomous items, where each item has five categories. They were used Graded Response Model as a single polytomous item response theory model to estimate items and individuals’ parameters. The study has used the Mantel-Haenszel (MH) way to detect (DIF) through each case for the different samples. The results of the study showed the inverse relationship between the sample size and the number of items, which showed a differential performer.

Acidizing is one of the most used stimulation techniques in the petroleum industry. Several reports have been issued on the difficulties encountered during the stimulation operation of the Ahdeb oil field, particularly in the development of the Mishrif reservoir, including the following: (1) high injection pressures make it difficult to inject acid into the reservoir formation, and (2) only a few acid jobs have been effective in Ahdeb oil wells, while the bulk of the others has been unsuccessful. The significant failure rate of oil well stimulation in this deposit necessitates more investigations. Thus, we carried out this experimental study to systematically investigate the influence of acid treatment on the geomechanical properties of Mi4

Different parameters of double pipe helical coil were investigation experimentally. Four coils were used; three with a curvature ratio (0.037, 0.031, and 0.028) and 11mm diameter of the inner tube while the fourth with 0.033 curvature ratio and 13 mm diameter of the inner tube. The hot water flow in the inner tube whereas the cold water flows in the annulus. The inlet temperatures of hot and cold water are 50 ⁰C and 18 ⁰C respectively. The inner mass flow rate ranges from 0.0167 to 0.0583 kg/s. The results show the Nusselt number increase with increase curvature ratio. The Nusselt number of the coil with 0.037 curvature ratio increases by approximately 12.3 % as compare with 0.028 curvature ratio. The results also r

The lead-acid battery has become so dependable in its used applications of automobile starting, emergency lighting and telecommunications, which left an impression that no further investigation is necessary or desirable. While there has been slow continuous improvements in lead-acid battery performance and mainly limited to design and material engineering. This work is mainly devoted to the properties of the active mass of the positive electrode and the acid/water ratio during the manufacturing process. A field study is carried out at the State Battery Manufacturing Company located in Baghdad, to prepare batches of lead mono-oxide with predefined quantities of liquid additives (i.e. sulfuric acid and water). Quality control and laborator

The research aims to demonstrate the impact of the acceptable solvency of the National Insurance Company on the investment activity in it, as the research assumes the existence of a statistically significant relationship between the acceptable solvency variable and the investment variable, and the researcher took the National Insurance Company as a place to conduct the research, as it is the first insurance company Watania was established in the fifties of the last century, and it has a long history in the practice of investment activity, and the company’s financial statements for the period from (2010-2019) were relied on, and the annual reports issued by the company as well as records are tools for gathering information, and

The marine collagens are biocompatible and biodegradable materials that are considered as a biomimetic approach for tissue regeneration. This study evaluated the effect of daily consumption of marine collagen supplement drink on enamel white spot lesions (WSLs), comparing the results against Regenerate system and Sylc air abrasion methods. Fifty human enamel slabs were allocated into five groups (n = 10 per group): non-treated (sound); non-treated (WSLs, 8% methylcellulose gel with 0.1 M lactic acid (pH 4.6) at 37 °C for 21 days); and three treated surfaces with marine collagen; Regenerate system; and Sylc air abrasion. The treatment lasted for 28 days followed by four weeks’ storage in artificial saliva (pH = 7.0, 37 °C). Evalu

The job that confronts players with the effectiveness of shooting with an air rifle is high, so it requires necessary functional adaptations that differ in their degrees from other sports. Regular training in air rifle shooting leads to physiological changes in most of the body's internal systems, and changes and responses can be identified. The functional accompanying physical activity through the presence of body components that reflect these physiological changes in the form of changes in some components, and the importance of research lies in studying the physiological changes accompanying the maximum physical effort and the consequent development of the level of achievement in the effectiveness of shooting with air rifle and body

The aim of the study is to reveal the effect of the constructivist learning Model on the achievement and reflective thinking of the fifth grade literary Preparatory students in History subject. A random sample was chosen which consisted of 64 students divided into experimental and control groups, each group consisted of 32 students. The experimental group was taught via the constructivist learning model, and the control group was taught via the traditional method. The experiment was lasted for Eight weeks, each week taught two lessons. The researcher adopted the experimental design with partial control. The two groups were equalized statistically. The researcher used two instruments, the achievement test and the reflective thinking test.