When the fluid flows over the surface, the surface will resist its motion. This is called drag. Aerodynamic drag is the sum of pressure drag and viscous drag. This research will focus on how rear end parameter will affect the drag coefficient of the sedan car. Although drag coefficient will not give a big effect towards the rear end of the vehicle in comparison to the front end, this research focuses its initial stages in studying what is the effect of rear end drag if present .16 common sedan vehicle models from the different segments are measured at the rear end profile to determine the maximum and minimum range of the rear end parameters. Seven rear end design parameter will be used in the designing process while the front end data will is taken from previous research. Using the DoE method, 79 units of car models were designed using CATIA software. ANSYS software will be used in this research for finding which rear end parameter will give the lowest drag coefficient value. From the findings, the lowest Cd value was 0.22495.

Full Text

Orthotic footwear requires a comfortable design to solve biomechanical foot issues such as walking, standing or running of the patients. In this case, the accurate geometrical data are needed by applying a 3D scanner. However, geometrical deviations of the final product may be often found in the manufacturing process related to the system or changing the CAD data format. The purpose of this research was to investigate the effect of the data transfer process on the geometry and morphology of the foot scanning results. Firstly, variations in data format from the patient's foot were obtained using 3D scanning with Handyscan 700 scanner, Einscan Pro 2X Plus, ScanPod 3D and photogrammetry method with a Canon EOS 500D camera. The second step involved the data transfer to the CAD modeller using Solidworks software. The results showed that the geometry and morphology of the scans from each scanner were indifferent and the variation of CAD data formats did not affect the geometry and morphology. In CAD software, the very large CAD data format is IGES, the result of a Handyscan 700 scanner with a file size of 38,864 KB. The smallest data format is the STL on the ScanPod 3D scan results of 671 KB.

Full Text

The prevalence of water related diseases has led to the critical need for water treatment before domestic use; water treatment usually comprises several processes needed to improve the quality of raw water. This research aimed at comparing the efficiency of Moringa seed extract on twelve drinking water quality parameters, evaluating and comparing the performance and effectiveness of Moringa seed extract to alum in different domestic water samples in Ikole-Ekiti, Nigeria. Moringa Oleifera extract was added to collected water samples which were subjected to laboratory investigations, results showed that the Moringa Oleifera seed extract improved the characteristics of odour, total solids, turbidity, pH, nitrate, chloride, hardness, iron and sulphate parameters in collected water samples; to levels that met standards for drinking water. It was recommended that private investors are encouraged to invest on the production and use of Moringa Oleifera based on its high economic value.

Full Text

This article deals with the design, simulation and construction of a fuel storage tank-chassis and a lifting system coupled as a single unit to a Cummins QSK19 engine driven HL260m pump that can guarantee an operating autonomy of up to 12 continuous hours and can be transported to different locations by means of lifting systems. For the mechanical design the recommendations of the American Institute of Steel Construction (AISC) and the application of the failure criteria for Von Mises ductile materials or Maximum Energy Distortion were used. For the dimensioning of the storage tank, the average consumption stipulated by the manufacturer was used and the simulations were performed with SolidWorks®. A functional and safe system that can be used in on-site applications was achieved.

Full Text

The sustainability of pavement slabs was analyzed using finite element models with Abaqus and EverFE to establish both surface and deep stress zones and the delimitation of damage. The stress results of finite element models with these two tools were verified with the results of the Westergaard analytical model. It was found that, in the case of load located at the edge of the slab -where the main stress is higher- the EverFE model is better verified with the analytical model while, in the load cases located at the corner and interior the slab -where stresses are lower-, Abaqus model is closer to the results of the analytical model, concluding that both tools are powerful and reliable for the analysis of stresses in pavement slabs. This type of analysis with a sustainable focus leads not only to better decision making in the design, management and construction of pavement slabs, but also to better conservation alternatives for these structures.

Full Text

Commonly, outcome of the end product in industry depends on the trajectory tracking performance of the machine. Concerning positioning or trajectory tracking, the endorsement of the control system to compensate the common drawback in most physical system is required. Thus, in this paper, three different control approaches are proposed and implemented in the Electro-Hydraulic Actuator (EHA) system. As a benchmark of the control system, the Proportional-Integral-Derivative (PID) controller is initially designed. Followed by the designs of an enhanced version of the PID controller, known as Fractional-Order (FO-PID) controller. Lastly, the designs of the robust Sliding Mode Controller (SMC) is carried out. Subsequently, the performance evaluation, particularly in trajectory tracking and controller effort are performed. To comprehensively analyse the output response, the data are extracted by using the popular performance indices including Root Mean Square Error (RMSE), Integral Square Error (ISE), Integral Time Square Error (ITSE), Integral Absolute Error (IAE), Integral Time Absolute Error (ITAE). In the past study, most of these indices are applied to analyse the error generated from the system. In this paper, all the performance indices are performed not only to the system error but including the energy consumption of each controller. It is observed in the results, based on the performance indices in terms of error and voltage, the SMC capable of generating better outcomes with reference to tracking capabilities and energy usage.

Full Text

Cross Flow turbine with multi nozzle is very suitable to be used as a power plant in rural areas to optimize the use of small or large scale water energy. Water energy is converted into mechanical energy in turbines and then mechanical energy is converted into electrical energy by generators. However, turbine performance must be improved by using a multi nozzle cross flow turbine and its maintenance is continuously maintained. Cross flow turbine with multi nozzle, turbine blades are able to absorb water energy greater than water jets through multi nozzle. Potential water energy is first converted into kinetic energy in the water turbine nozzle. The spray jet of water coming out of the nozzle that has a high speed is able to move the turbine blade, resulting in high rotation in the multi-nozzle cross flow turbine so that it is very effective to improve the performance of the cross flow turbine as an electric generator drive.

Full Text

In this work, two controllers, a Proportional Integral (PI) and a Model-based Predictive Controller (MPC), have been designed to regulate a non-linear liquid level system. First, the modeling and linearization of the system was performed using Taylor series. Then the PI controller was designed around a certain set point. Next, an algorithm was designed according to the Extended Prediction Self-Adaptive Control (EPSAC). Finally, the performance of the controllers is evaluated for set point tracking and disturbance rejection.

Full Text

A finite elemental algorithm has been developed for calculating an arbitrarily loaded shell, the reference surface of which is determined by Cartesian coordinates , which are functions of curvilinear coordinates . For an arbitrary point of the shell located at a distance from the reference surface, the radius vector characterizing its position is determined by the sum of the radius vector of the corresponding point of the reference surface and the normal vector to the reference surface with the component . By differentiating the radius vector of an arbitrary shell point by curvilinear coordinates and by coordinate , three basis vectors of the considered arbitrary shell point are determined in the form of a function of the unit vectors of the Cartesian coordinate system. By differentiating the radius vector of an arbitrary shell point with respect to curvilinear coordinates and a normal coordinate , using the matrix relation between the Cartesian coordinate system orts and the basis vectors of the point under consideration, matrix expressions of the derivatives of the basis vectors of the considered point in the basis components of the same point are obtained. The specified load was determined in the components of the basis vectors of the point of application of the load. The displacement vector of an arbitrary point of the shell was represented by the components of its basis vectors. The derivatives of the displacement vector along the curvilinear coordinates and along the coordinate along the normal were determined taking into account the change in the basis vectors of the point under consideration. The components of the strain tensor at an arbitrary point of the shell were determined by the relations of continuum mechanics as the difference of the metric point tensors in the deformed and initial states. As volumetric finite elements, prisms with bases in the form of a triangle and a quadrangle with orientation of the bases in surfaces approximately parallel to the reference surface are taken. Nodal unknowns of volumetric finite elements accepted displacements and their first derivatives. The triangular prism was represented by three tetrahedra, the stiffness matrices of which were formed using Lagrange correction factors, which allow improved compatibility in the midpoints of the sides of the triangular bases of adjacent prismatic elements. To form the stiffness matrix of the tetrahedral element, we used the conditional Lagrange functional when adding terms with correction factors. On the example of calculating the strength of a fragment of a thin-walled tank for storing fuel and lubricants of the agro-industrial complex in the form of an elliptical cylinder, the efficiency of the developed finite element algorithm is shown.

Full Text

The study on vegetable oil-based drilling mud has gained much attention due to the detrimental effects of the conventional oil-based mud (OBM). The conventional OBM contains additives which can endanger the safety of personnel handling it. The objective of this study is to formulate a new OBM by using coconut oil as a base fluid and analyze whether coconut oil-based mud would be a viable option as opposed to conventional mineral oil. Coconut oil will be used as a substitute to the conventional base oil. The compared properties were rheological properties, yield point, gel strength and filtration loss properties. The mud density for both drilling mud is kept constant at 9.0 ppg for comparison purpose. Results obtained show that the Coconut OBM exhibited Bingham plastic rheological model with high yield point and gel strength compared to OBM. Furthermore, the mud filtration test results were 3.8 ml for Coconut OBM and 1.7 ml for OBM. The thicker mud cake of Coconut OBM would cause pipe to stuck compared to OBM thinner mud cake. In conclusion, Coconut OBM exhibit poor performance in mud rheology and filtrate loss with the exception of superior gel strength than OBM but it is not sufficient to replace OBM in any drilling operations.

Full Text

In this paper, a new approach for the economic environmental dispatch (EED) problem with both wind turbines and thermal generators is presented. The here-and-now (HN) strategy is used in the problem formulation by incorporating the stochastic characteristic of the wind power (WP) in the system constraints. Weibull probability distribution function (PDF) is employed to describe the WP. An elitist optimization approach based on particle swarm optimization and the non-dominated sorting concept is applied to solve the stochastic and non-smooth EED problem. The suggested framework is successfully evaluated on the 69-bus ten-unit system.

Full Text

Abstract:

The article provides data on aspects of the effective use of irrigated land in southeast Kazakhstan. For this, the authors calculated the effective heat sum needed for crops and the actual values of this parameter in southeast Kazakhstan. Based on this data and the results of field research, aspects of the effective use of irrigated lands in the southeastern region of Kazakhstan were established. For the effective use of irrigated lands and an increase in their productivity, the authors recommend sowing intercrops after the basic crops, which contributed to the increase in the profitability level from 129% to 149%. According to the results of field experiments, the highest net income of 171-197 thousand tenges per hectare was obtained by sowing intercrops after the basic crop (winter triticale). Usage of Sudan grass as an intercrop for the herbage production did not produce any effect.

Full Text