This paper presents L₁-adaptive controller for controlling uncertain parameters and time-varying unknown parameters to control the position of a DC servomotor. For the purpose of comparison, the effectiveness of L₁-adaptive controller for position control of studied servomotor has been examined and compared with another adaptive controller; Model Reference Adaptive Controller (MRAC). Robustness of both L₁-adaptive controller and model reference adaptive controller to different input reference signals and different structures of uncertainty were studied. Three different types of input signals are taken into account; ramp, step and sinusoidal. The L₁-adaptive controller ensured uniformly bounded

In this study NiO - CoO bimetallic catalysts are prepared with two Ni/Co ratios (70:30 and 80: 20) using the precipitation method of nitrate salts. The effects of Ni /Co ratio and preparation methods on the catalyst are analyzed by using different characterization techniques, i.e. atomic absorption (AA) , XRD, surface area and pore volume measurements according to the BET method . The results indicate that the best catalyst is the one containing the percentage of Ni :Co ( 70 : 30 ). Experiments indicate that the optimal conditions to prepare catalyst are stirring for three hours at a temperature of 60oC of the preparation , pH= (8-9) , calcination temperature at 400oC for two hours

Abstract  

This research aims to study and improve the passivating specifications of rubber resistant to  vibration. In this paper, seven different rubber recipes were prepared based on mixtures of natural rubber(NR)  as an essential part in addition to the synthetic rubber (IIR, BR_cis, SBR, CR)with different rates. Mechanical tests such as tensile strength, hardness, friction, resistance to compression, fatigue and creep testing in addition to the rheological test were performed. Furthermore, scanning electron microscopy (SEM)test was used to examine the structure morphology of rubber. After studying and analyzing the results, we found that, recipe containing (BRcis) of 40% from th

Oilwell cementing operations are crucial for drilling and completion, preserving the well's productive life. However, weak and permeable formations pose a high risk of cement slurry loss, leading to failure. Lightweight cement, like foamed cement, is used to avoid these difficulties. This study is focused on creating a range of foamed slurry densities and examining the effect of gas concentration on their rheological properties. The foaming agent and foam stabilizer are tested, and the optimal concentration is determined to be 2% and 0.12%, respectively, by the weight of the cement.

Furthermore, the construction of samples of foam cement with different densities (0.8, 1.0, 1.2, 1.4, and 1.6) g/cc is performed to f

The development taking place on the sports field at the general level and in the game of football at the private level, being the most popular game in the world, has reached very advanced stages. The use of modern aids and technology has contributed greatly to this development from the collective and individual aspects, as the goalkeeper is the most important position in the team, the use of devices gave objective readings about the goalkeeper’s ability in terms of skill and physical aspects, as the importance of the research lies in designing an electronic device to measure the degree of bending of the knee angle because of its great importance in developing the skill of catching and dimensions of the high ball for football goalkeepers.

The research dealt with the effectiveness of prediction and foresight in design as a phenomenon that plays a role in the recipient's engagement with the design, as it shows the interaction between the recipient and the interior space. The designer is keen to diversify his formal vocabulary in a way that secures visual values that call for aesthetic integration, as well as securing mental and kinetic behavioral understanding in the interior space.
As the designer deals with a three-dimensional space that carries many visual scenes, the designer should not leave anything from it without standing on it with study and investigation, and puts the user as a basic goal as he provides interpretive data through prediction and foresight that le

This article discusses the peculiarities of the Arabic root, its phonemic structure, and morphological categorization. The pure appearance of the Arabic root in language categorization allows you to separate the onomatopoeic feature of inflectional structure and phonetic rules of the Arabic language by which the root is categorized. This phenomenon of meaningful consonant phonemes in the Arabic roots makes the theory of onomatopoeia practicable not just only in Arabic but also in other Semitic languages. Moreover, the first consonant of an Arabic root usually contains the word's primary, essential meaning, and the second and third lookup. Also, in this work, it is noted that the grammar of the Arabic language has many features aimed

Different Arabic and Islamic societies are free of evil instincts. Therefore, certain provisions of legitimacy came to stress the importance of the intentions of sharia to achieve the interests of all people that involve several aspects, including the five fundamental things: religion, oneself, offspring, mind and money. Almighty Allah has specified certain punishments on those who violate these things by imposing punishments on the part of the criminal to preserve souls. He imposes the penalty of theft to preserve property, the Hadd punishment for adultery to preserve the symptoms, the punishment on the drunk to preserve the mind, and the Hadd punishment for the apostate to preserve the religion. By the adherence to these punishments li

Began research of the foundations of Orientalist discourse based on force and metadata and authority, and the possibility of turning the West's view of the East as if made ​​radical changes in the structure of the West or in a relationship of power and authority between it and the east. We have adopted in our paper on the research categories of Edward Said and visions in the field of Orientalism in general, and especially his book entitled the name of this area, not forgetting, or leave the expansion to other sources, a researcher in this field, to enrich the research.

We went to Orientalism as a concept and based cognitive, and the work of the Orientalist, and the meanings of Orientalism, which suggests Balastala which was c