This paper presents the application of the generalized differential quadrature (GDQ) method for the hydrodynamic analysis of circular AND noncircular, two lobe AND three lobe, journal bearings. GDQ is a simple, efficient, high-order numerical technique AND it uses the information on all grid points to approach the derivatives of the unknown function. The effectiveness of the solution technique is verified by comparing the GDQ computed results with that of analytical solutions AND FDM results from the published literature. It is found that GDQ method can easily compete with the existing methods of solution of lubrication problems for its analytical simplicity, smaller computer storage requirements AND capability of producing accurate results with very high computational efficiency. Also the effects of design AND assemble parameters, namely the eccentricity ratio, preload factor, MOUNT AND TILT ANGLES on the performance parameters of these bearings have been investigated using GDQ method. Results show that the variation of MOUNT AND TILT ANGLES can has variable effects on noncircular lobed journal bearing performance parameters. Among the two types of noncircular bearings considered, the effect of the MOUNT AND TILT ANGLES is more significant for two lobe bearings in comparison with the three lobe bearings.

The maneuverability of a quadrotor or octorotor UAV is limited in the stANDard configuration ‎because the force vectors of the propellers are parallel AND only have four active degrees of ‎freedom. Therefore, they lack the controllability of six independent degrees of freedom. This ‎study designs a novel configuration for an octorotor capable of hovering with roll or pitch ANGLES in ‎a specific position, contrary to UAVs with a stANDard configuration that can only hover in a ‎horizontal position. In other words, in this octorotor, orientation tracking is also added to the ‎octorotor's targets in addition to position tracking. The proposed model can be controlled by ‎altering the velocity of the eight rotors AND the TILT angle of the four arms. Such alterations in ‎velocity AND TILT angle are such that they can provide the aerial vehicle with most optimum ‎maneuverability. After deriving the proposed dynamic octorotor model, a controller is proposed ‎using neural networks (NNs) AND reinforcement learning (RL), capable of controlling the proposed ‎octorotor with six independent degrees of freedom. Finally, trajectory tracking, octorotor position, ‎AND controller robustness to possible motor malfunctions are examined, AND numerical simulation ‎results are provided.‎

This work optimises the collection of solar energy within the period of its availability in order to increase its utilisation AND also to enhance performance of heating systems that depend on it through appropriate determination of optimum solar collector TILT ANGLES. Buoyancy-induced flow equation in solar collector pipe was established by continuity, energy AND Navier–Stokes equations in cylindrical coordinates. Fundamental solar radiation equations were programmed to determine optimum TILT ANGLES in locations within latitudes 1o AND 14o. A set of data recorded from a pryanometer located on latitude 6.45o north of the equator was used to generate average monthly radiation over the latitudes. Graphs obtained from latitude 6o AND 13o data were analysed to investigate solar radiation on some TILT ANGLES. The optimum TILT ANGLES for solar heating for periodic tracking of the sun in the region within latitudes 1° AND 14° were predicted as Æ+25° for November, December AND January, Æ+15o for February, September AND October, Æ-15o for August, Æ-25o for May, June AND July, AND Æ for March AND April. The results of this work confirmed that solar radiation on TILTed surface increases with latitude.

Noncircular lobed journal bearing performance, in comparison with circular types, depends on various design parameters such as TILT AND MOUNT ANGLES. MOUNTing orientation of this kind of bearings with respect to machine frame (MOUNT angle) AND also the way of setting their lobes with respect to each other (TILT angle), can change the bearings configuration AND, as a result, their performance. In present study the thermo-hydrodynamic performance of noncircular two, three AND four lobed journal bearings for different values of TILT AND MOUNT ANGLES, using generalized differential quadrature (GDQ) method, are investigated. The results show that the thermal effects on these bearings performance are considerable AND that the thermal consideration makes the results closer to real performance situations. The results of bearings performances due to rise in temperature in rotor, lubricant fluid AND bearing shell, when compared to their isothermal conditions, show that viscosity of lubricant as well as load carrying capacity of bearings are decreased, depending on TILT AND MOUNT ANGLES, especially in case of two lobed bearings. The results also show that the effects of TILT AND MOUNT ANGLES on bearing performance are periodic AND so it is possible to select these ANGLES suitably for bearings to be optimum.

One of the main problems in using solar panels is dust which reduces their efficiency. In the present paper, the effect of dust AND the angle of installation of the photovoltaic panel on its performance loss in the city of Ilam have been investigated. The experiments were performed using two similar panels in the spring by considering different aMOUNTs of dust from 0 to 236.94 g/m2. Voltage, current, AND power losses were calculated AND the effects of dust AND panel angle on them were investigated in a multi-factor experiment based on a completely rANDomized design. The effect of dust on voltage, current, AND power loss was significant at 1% probability level, AND their losses increased with an increase in the aMOUNT of dust. The lowest performance loss was related to voltage which varied between 1.53% at an angle of 4.8° AND the aMOUNT of dust at 236.94 g/m2 AND 7.84 % at an angle of 26.1° AND the aMOUNT of dust at 72.28 g/m2. The output current has a greater loss than the voltage, AND its highest value (87.19%) was observed in the panel at the angle of 26.1° AND the aMOUNT of dust at 236.94 g/m2AND its lowest value (24.8%) at the angle of 26.1°AND the aMOUNT of dust at 42.85 g/m2. The highest power loss (87.5%) was related to the angle of 26.1°AND the aMOUNT of dust at 236.94 g/m2, AND the lowest loss (26.5%) was related to the angle of 26.1° AND the aMOUNT of dust at 42.85 g/m2. It was found that the angle determined based on the geographical location (26.1°) has a lower performance loss than the other ANGLES AND, therefore, is a more suitable angle for generating electrical energy in the event of dust.

It is now a well-recognized fact that bearings play a vital role in the performance of any rotor bearing system.Though the plain journal bearing is the oldest AND a general purpose bearing configuration, it does not suit the requirements of modern high speed rotating systems AND precision machine tools. In such specialized applications, the plain journal bearing has mostly been replaced by noncircular two AND three lobe bearings which exhibit superior dynamic performance. In contrast to the plain circular bearing, noncircular journal bearing may be oriented in various ways with respect to a given direction of external load. This orientation may be described in terms of an angle, which in the present work has been referred to as the MOUNT AND TILT ANGLES. In the present work applying GDQ method, analyses of micro polar lubricated circular AND noncircular two AND three-lobe journal bearings, are presented.Effects of micro polarity characteristics of lubricant, design AND assemble parameters on the performance parameters of these bearings have been investigated. In general, results show that micro polar characteristic parameters of the lubricant improve the performance of the circular AND noncircular bearings. Also it is observed that in the noncircular bearing the effect of MOUNT AND TILT ANGLES is generally marginal. of the two types of bearings considered, the two lobe bearings are most sensitive to MOUNT AND TILT ANGLES. However, the MOUNT AND TILT ANGLES are assemble AND design parameters, but sometimes they can be selected just to meet some specific operation goals.