Poly vinyl alcohol has been studied for its ability to form crystallites by using annealing method. Semicrystalline films of poly vinyl alcohol (PVA) were prepared by casting 11.5 wt. % and 13 wt. % PVA aqueous solution onto glass slides at annealing temperature range 90 -120°C and duration time 15- 60 minute. This allowed the macromolecules to form crystallites, small regions of folded and compacted chains separated by amorphous regions where single PVA chain may pass through several of these crystallites. Degree of crystallinity of PVA films (hydrogels) was determined by method of density; on the other hand the swelling behavior was conducted by the determination of water uptake, wet degree of crystallinity, gel fraction and solubility. The results of PVA films showed that water uptake decreased with increasing temperature, time of annealing and PVA concentration, while degree of crystallinity increased, and gel fraction and solubility decreased with increasing temperature and time of annealing. The maximum dry and wet degree of crystallinity was 64% and 36% respectively at 120°C and 60 min.
يلعب القطاع الصناعي التحويلي في أي قطر دوراً هاماً في تحقيق التنمية الصناعية، اذ تتحد تاثيراته فيها على طبيعة الدور المرسوم له وعلى مدى فاعلية هذا القطاع الحيوي الذي يعد اتجاه نحو التعاظم المضطرد لمستويات الانتاجية " Levels of productivity"والتنويع الانتاجي والتدفق المستمر للتجديد التكنولوجي من اهم دلائله.
ويعد مؤشر الانتاجية بصفة عامة وانتاجيتي العمل وراس المال بصفة خاصة من الم
... Show MoreBall and Plate (B&P) system is a benchmark system in the control engineering field that has been used to verify many control methods. In this paper the design of a sliding mode . controller has been investigated and verified in real-time via implementation on a real ball and plate system hardware. The mathematical model has been derived and the necessary parameters have been measured. The sliding mode controller has been designed based on the obtained mathematical model. The resulting controller has been implemented using the Arduino Mega 2560 and a ball and plate system built completely from scratch. The Arduino has been programmed by the Arduino support target for Simulink. Three test signals has been used for verification purposes
... Show MoreThis paper proposes a new structure for a Fractional Order Sliding Mode Controller (FOSMC) to control a Twin Rotor Aerodynamic System (TRAS). The new structure is composed by defining two 3-dimensional sliding mode surfaces for the TRAS model and introducing fractional order derivative integral in the state variables as well as in the control action. The parameters of the controller are determined so as to minimize the Integral of Time multiplied by Absolute Error (ITAE) performance index. Through comparison, this controller outperforms its integer counterpart in many specifications, such as reducing the delay time, rise time, percentage overshoot, settling time, time to reach the sliding surface, and amplitude of chattering in control inpu
... Show MoreThis paper deals with a Twin Rotor Aerodynamic System (TRAS). It is a Multi-Input Multi-Output (MIMO) system with high crosscoupling between its two channels. It proposes a hybrid design procedure that combines frequency response and root locus approaches. The proposed controller is designated as PID-Lead Compensator (PIDLC); the PID controller was designed in previous work using frequency response design specifications, while the lead compensator is proposed in this paper and is designed using the root locus method. A general explicit formula for angle computations in any of the four quadrants is also given. The lead compensator is designed by shifting the dominant closed-loop poles slightly to the left in the
... Show More74 fanners were randomily selected from the Lc:ital. of 406 fanners using the Modern Irrigation System up to November , 2000 , for the purpose of wide adoptation of such system. Rcsults indicated according to the data which has been obtained and statistically analysed by the statistical package for the Social Sciences (SPSS) program showed that the majority of the farmers adopted this new system of irrigation due to the increase in the yield up to 5" .
The performance of a solar assisted desiccant cooling system for a meeting-hall located in the College of Engineering/University of Baghdad was evaluated theoretically. The system was composed of four components; a solar air heater, a desiccant dehumidifier, a heat exchanger and an evaporative cooler. A computer simulation was developed by using MATLAB to assess the effect of various design and operating conditions on the performance of the system and its components. The actual weather data on recommended days were used to assess the load variation and the system performance during those days. The radiant time series method (RTS) was used to evaluate the hourly variation of the cooling load. Four operation modes were employed for perform
... Show MoreA concept of indoor solar illumination is described and simulated. The solar illumination system is composed of a tracking primary reflector, a selective secondary reflector, a visible light guide and a scattering solid glass tube fixture. Each part of the solar illumination system is optically suited and compatible with other parts to realize high efficiency. The simulation is conducted for Baghdad city for a library hall. Two major days over a year are chosen to investigate the illumination system for acceptable visible light level for reading hall. The two days are: summer solstice day and winter solstice day at 8:00 AM and 12:00 PM for each. Research results showed that the design of the solar system is achieved on the base of minimu
... Show MoreDC planar sputtering system is characterized by varying discharge potential of (250-2000 volt) and Argon gas pressures of (3.5×10-2 – 1.5) mbar. The breakdown voltage for silver electrode was studied with a uniform electric field at different discharge distances, as well as plasma parameters. The breakdown voltage is a product of the Argon gas pressure inside the chamber and gab distance between the electrodes, represent as Paschen curve. The Current-voltage characteristics curves indicate that the electrical discharge plasma is working in the abnormal glow region. Plasma parameters were found from the current-voltage characteristics of a single probe positioned at the inter-cathode space. Typical values of the electron temperature an
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