In the present work, the surface properties of mixed binary surfactants containing sodium dodecylbenzene sulfate (SDBS) and Tween 80 (TW80) surfactants in aqueous solutions were studied at temperature 293 K using surface tension measurements. The critical micelle concentration (cmc) magnitude for both individual surfactants and their mixtures were established the obtained results revealed that the magnitude of cmc of the mixtures are less than the magnitude of individual surfactants and decrease with the increase in Tween 80 percent in solution which indicate the nonideal mixing of the two surfactants. The values of molecular interaction parameters and the mole fraction of surfactants in the micelle (X1) were calculated on the basis of Rubingh’s model and showed that the interaction parameter is always negative but at 0.9 mole fraction of TW80 surfactant (α1) is positive
This paper describes a new finishing process using magnetic abrasives were newly made to finish effectively brass plate that is very difficult to be polished by the conventional machining processes. Taguchi experimental design method was adopted for evaluating the effect of the process parameters on the improvement of the surface roughness and hardness by the magnetic abrasive polishing. The process parameters are: the applied current to the inductor, the working gap between the workpiece and the inductor, the rotational speed and the volume of powder. The analysis of variance(ANOVA) was analyzed using statistical software to identify the optimal conditions for better surface roughness and hardness. Regressions models based on statistical m
... Show MoreThe flexible joint robot manipulators provide various benefits, but also present many control challenges such as nonlinearities, strong coupling, vibration, etc. This paper proposes optimal second order integral sliding mode control (OSOISMC) for a single link flexible joint manipulator to achieve robust and smooth performance. Firstly, the integral sliding mode control is designed, which consists of a linear quadratic regulator (LQR) as a nominal control, and switching control. This control guarantees the system robustness for the entire process. Then, a nonsingularterminal sliding surface is added to give a second order integral sliding mode control (SOISMC), which reduces chartering effect and gives the finite time convergence as well. S
... Show MoreThe adsorption ability of Iraqi initiated calcined granulated montmorillonite to adsorb Symmetrical Schiff Base Ligand 4,4’-[hydrazine-1, 2-diylidenebis (methan-1-yl-1-ylidene)) bis (2-methoxyphenol)] derived from condensation reaction of hydrazine hydrate and 4-hydroxy-3-methoxybenzaldehyde, from aqueous solutions has been investigated through columnar method.The ligand (H2L) adsorption found to be dependent on adsorbent dosage, initial concentration and contact time.All columnar experiments were carried out at three different pH values (5.5, 7and 8) using buffer solutions at flow rate of (3 drops/ min.),at room temperature (25±2)°C. The experimental isotherm data were analyzed using Langmuir, Freundlich and Temkin equations. The monol
... Show Moreرمت الدراسة التعرف بمستويات التفكير الهندسي لدى طلبة قسم الرياضيات في كلية التربية / ابن الهيثم - جامعة بغداد، ولتحقيق هدف الدراسة تم اعتماد مقياس الحربي(2003) المعد على البيئة السعودية ويتكون من (25) فقرة موزعه على خمسة مستويات وهي (المستوى البصري ، التحليلي ، شبه الاستدلالي، الاستدلالي، المجرد وبلغت عينة الدراسة (206) طلاب من طلبة قسم الرياضيات في كلية التربية- ابن الهيثم بجامعة بغداد تم اختيارهم بالطريقة ال
... Show MoreInsurance companies play a dual and vital role in the economy in which they operate in two directions. The first is to protect investments from the various risks that threaten them by paying compensation in the event of one of these risks, which prevents companies from leaving the economic cycle and achieving social benefit because of continuity of the company means continuity The payment of taxes to the state and the payment of salaries and wages to employees and employees, in addition to the economic ties in front and background, which integrate the company with other companies (that stop the company can lead to the cessation of other companies), the second trend is that the trap The insurance company obtains the amounts of insurance p
... Show Moreالمقدمة
تمثل الأسعار تعبيرا" نقدياً لقيمة السلع والخدمات المقدمة للزبون، وتعد عملية التسعير من العمليات المهمة وذات الأثر البالغ على نجاح واستمرار منظمات الأعمال، نظراً لما لها من تأثير على المقدرة الربحية وإعادة توزيع الدخل القومي المخصص للاستهلاك، إذ أنه بتحديد الأسعار يستطيع الفرد أن يوزع دخله بين ما يعده ضرورياً من السلع وما يعد كمالياً.
وعموماً فإن لعملية التسعير م
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