Yanbu Journal of Engineering and Science (YJES)
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Direct Current Servo Motor Speed Characterization Using Proportional and Integral Controllers
No full textThe present study is focused on investigating the steady-state and transient responses of a DC servo motor controlled by the Proportional and Integral controllers. It is also studied how the P and I controllers affect the stability, error, and damping of the DC motor response. The DC servo motor responses are obtained experimentally using a servo trainer and a PI analog controller, and theoretically using MATLAB Simulink. It is found through the results that the P controller contributes to decreasing the input-output errors of steady-state and transient responses and tends to stabilize the system. It also speeds up the system response. On the other hand, the I controller tends to diminish the error but with sluggish response and affects the system’s stability with oscillations. Also, the Simulink results show that the optimized PI controller gains (Kp = 1.0363 and Ki = 1.9438) significantly reduce the overshoot and settling time. Through the present work, it is desired to obtain a stable response of the DC servo motor to the steady-state and transient input signals. The novelty of the present work is developing a PI controller-based nonlinear model for the DC servo motor speed control and optimizing the PI controller gains for the motor’s optimum performance
Machine Learning Modeling Approaches for Predicting the Extent of Fatigue Damage in Polycrystalline Alloy Structures
No full textUsing predictions of crack-tip-opening-displacement (CTOD) to measure the extent of fatigue damage has provided the opportunity to prepare an efficient strategy for protecting mechanical structures from damage and developing a structural health monitoring system. The objective is to forecast non-measurable CTOD by using machine learning methods. In this paper, an optical metrology device, which is built by Alicona on a confocal microscope and hereafter referred to as Confocal Microscope, has been used to measure CTOD. However, two factors limit the usage of Alicona Apparatus: (i) the size of optical images, where a CTOD over 400 micrometers cannot be measured; and (ii) the need to protect the device, as a CTOD over 150 micrometers has a significant impact on the safety of Confocal Microscope. Therefore, this paper has utilized Gaussian Processes (GP) and the Support Vector Machine (SVM) to forecast the non-measurable CTOD. Four machine learning metrics, mean average error (MAE), mean square error (MSE), root mean square error (RMSE) and R-squared error have been used in this study to evaluate the performance of the regression models. The results indicate that the GP model provides a better estimate of the current CTOD measurements. However, the SVM model provides a better forecast of future CTOD data based on the behavior of the CTOD rate
Numerical and computational fluid dynamics analysis of airflow in the air intake manifold of a 1.8L engine with respect to different intake velocity
No full textThe intake air manifold is a vital part of any internal combustion engine. The main purpose of the air intake manifold is to provide sufficient air to each cylinder and also equal distribution of air flow for each runner. The air needed to be distributed evenly within the runners, to achieve the maximum efficiency and performance of the engine. The present study is performed on the air intake manifold used over a 1.8-liter Dual Overhead Cam Engine (DOHC) in-Line16-valve 4-cylinder engine (2015 Model). The main objective of this study is to perform computational fluid dynamics (CFD) analysis using Ansys – Fluent package. The analysis is performed using steady-state and transient conditions. The simulations are performed by varying the air intake velocity, also the effect of each runner with references to the time (Transient). The mathematical calculation is performed to having different boundary conditions to enhancing the analysis. The results obtained for the outlet velocity using mathematical calculation 113m/sec and that of simulation is 79m/sec. This paper mainly focuses on the flow simulation study of the air-intake manifold using Ansys CFD Fluent for the four outlet runners with regards to the different inlet velocity. Furthermore, the study is incorporated by the mesh resolution method by using three different values such as (0, 4 and 7). This method can be adopted for any air-intake system and a comparative study can be performed
AQUEOUS MEDIATED DIELS-ALDER REACTION: A SIMPLE ROUTE TO THE SYNTHESIS OF PIPERIZINE DERIVATIVES
No full textWater is the most environmentally benign inexpensive solvent, and therefore aqueous mediated organic reactions constitute the ideal green chemistry. We herein report an environment friendly Diels Alder reaction of biologically active dihydropyrimidine (DHPM) as dienophile with glyoxime, dimethyl glyoxime and diaminoglyoxime as diene using water as solvent. Though the reaction was slow at room temperature, rate enhancement was observed when it was carried out at the reflux temperature. Further the reaction was also found to proceed smoothly with N-phenyl maleimide as dienophile
HEAT SAVING IN EVAPORATIVE CRYSTALLIZATION BY INTRODUCING A HEAT PUMP
No full textParticle Imaging Velocimetry (PIV) has been recognized as an essential and very useful technique for analyzing two or three- dimensional complex flow fields and two-phase fluid flows. PIV techniques promise to give improved results because they provide a visual solution taking the total field into account. In addition, PIV offers many advantages for the study of fluid flow. PIV is a measuring technique that allows us to capture the flow velocity of whole flow fields in a fraction of a second. Hence, PIV has become more and more popular and it has rapidly spread in the world being recognized as the most advanced flow velocimetry because of its strong merits. Its application ranges have been expanding to measure turbulent flow, multiphase flow, internal flow of fluid machines, bioengineering, medical engineering, environmental engineering, energy engineering, development of new materials, sports science, life science, mechatronics, robotics and so on. Furthermore, PIV has been recognized as a powerful new measuring tool in thermal and fluid engineering fields including multiphase flows. Thus, PIV is a very promising powerful tool in the study of the structure of flows. In this paper, the principles and the typically used methods of PIV measurement are summarized. The classification of PIV methods is also explained
A MULTISINK ENERGY-EFFICIENT ROUTING PROTOCOL FOR WIRELESS BODY AREA NETWORK
No full textRapid advancements in wireless sensor network have significantly supported the wireless body area networks (WBAN). In WBAN, especially in medical application, the energy efficiency of the sensor nodes is critical in the Intra-body communication level. In this case, the communication occurs between the sensor nodes (placed inside the human tissue) and sink node (placed on the human skin). Thus, replacing the battery of these sensor nodes is challenging. Several studies in Intra-body communication have focused on reducing the energy consumption by decreasing the distance required to transmit the sensed data. However, the stability of the system (overall lifetime of the system) is not achieved due to the variation in the lifetime of the sensor nodes. Herein, some sensor nodes act as relay nodes. These relay nodes are responsible for sensing, receiving, and aggregating the sensed data from the neighboring sensor nodes, and further sending it to the sink node. The present study describes a unique approach to achieving an energy- efficient routing protocol that guarantees a prolonged lifetime of the sensor, thereby stabilizing the system. Moreover, the peer-to-peer communication between the sensor and sink nodes is also investigated with respect to the mobility model. In conclusion, this study aims to remove the burden from sensor nodes by using multiple sink nodes in order to achieve the shortest distance of communication between the sensor and sink nodes, which could prolong the lifetime of sensor nodes and the overall stability of the system
THERMODYNAMICS ANALYSIS OF HEAT PUMP ASSISTED CRYSTALLIZATION PROCESS
No full textIn this work, the theoretical calculations were carried out for a heat pump assisted crystallization process. The studied method includes a heating process of mother liquor in a crystallizer for direct evaporative crystallization. R-134a is used as refrigerant. The coefficient of performance (COP), exergetic efficiency (17), and total irreversibility rate were calculated. It was also found that the highest irreversibility value was at condenser temperature of 25°C and evaporative temperature of -15°C. It was also found that the salt concentration in a slurry solution (XD) inside a crystallizer increases as COP increases
SPECTROPHOTOMETRIC DETERMINATION OF HEXAVALENT CHROMIUM CONTENT IN COMMERCIAL CEMENT SAMPLES BY A SIMPLE AND RAPID PROCEDURE FOR THE EXTRACTION AND ANALYSIS OF CHROMIUM (VI)
No full textA simple and rapid procedure for the extraction and analysis of chromium by spectrophotometric method has been developed. Throughout the world the content of hexavalent chromium in cement is under control. In Europe, the new restrictions on the amount of this substance prohibit the use of cement having concentration more than 2 ppm. However, hexavalent chromium contents in cements above 2 mg kg¹ are still found frequently. The study represents a contribution to the establishing of possible limitations of this compound. The analyses showed that 7 of 10 cement samples analyzed by us satisfy the requirements for limit value of 2 ppm for water-soluble chromium (VI) in cement available in our market. Chromium (VI) was analyzed using the reference diphenylcarbazide spectrophotometric method from TRGS 613. The results for the absorbance spectra showed that maximum absorbance peak of the hexavalent chromium complex was at 538.7 nm. It was recorded in the range 25-200µg Cr(VI) L¹ using Varian Cary 50 reader system. This study presents a new procedure for chromium extraction. Parameters such as extraction time in dependence of the rotary of the stirring and wavelength variation were optimized and the results obtained were satisfying. In the present work a cement sample from the Devnya manufacturer was tested and it was found that this cement satisfies the European standard requirements. Finally, this application describes a simple and rapid, cost-effective analysis to measure low levels of hexavalent chromium
SIMPLE SPECTROPHOTOMETRIC DETERMINATION OF SELECTED CEPHALOSPORINS USING THIONIN
No full textA simple spectrophotometric method for the determination of cephalosporin antibiotics as pharmaceutical ingredient, namely cefotaxime, ceftriaxone, cefadroxil and cefalexin using thionin is described. The method is based on the hydrolysis of B-Lactam ring of with sodium hydroxide which subsequently reacted with potassium iodate in acidic medium to liberate iodine. The liberated iodine bleaches the violet color of thionin, which measured at 600 nm. The decrease in absorbance is directly proportional to the concentration of cefotaxime, ceftriaxone, cefadroxil and cefalexin. Beer\u27s law is obeyed in the range 0.5 6.4 µg mL. 0.4 5.2 µg mL, 0.8 4.2 µg mL and 1.0 7.5 µg mL for cefotaxime, ceftriaxone, cefadroxil and cefalexin respectively. The molar absorptivity was found to be 7.21 x 10 Lmol\u27cm for cefotaxime, 1.23 x 10° Lmol \u27cm for ceftriaxone, 6.91 x 10 Lmol cm for cefadroxil and 4.08 x 10 Lmol\u27cm for cefalexin. The method has been successfully applied to the determination of cefotaxime, ceftriaxone, cefadroxil and cefalexin in various pharmaceutical samples
AN EXPRESS ANALYSIS OF A LOCAL NETWORK CATALOG OF EARTHQUAKES IN THE REGION OF QUETTA, PAKISTAN
No full textEarthquake catalogs are a valuable result of fundamental seismological practice and they form the basis for seismicity, seismotectonic, seismic risk and hazard investigation. Before one proceed in such investigation it is essential to examine and report on the spatial and temporal homogeneity and completeness of the catalog. As it is well known fact that man made inhomogeneities and artifacts exist in earthquake catalogs that are produced by changing seismological networks. In this paper we are focused on the analysis of local catalog for the region Quetta, of Pakistan, as this region has a history of many large earthquakes. The local catalog considered here is referred from the International Seismological Center (ISC). The catalog contains information from 01- 01-1992 to 30-06-2006. The catalog covers an area Latitude 28.00 to 32.000 N, Longitude 65.00 το 69.000 E and contains 690 events. To examine and report on the spatial and temporal homogeneity and completeness of the local catalog its comparison is done with the Global Catalog of National Earthquake Information Center (NEIC) of USA. Finally to get a homogeneous catalog for the region, we merge the two catalogs by considering different data properties and different data analysis techniques prepared by different data collection agencies. The merged catalog is rather homogeneous as variation in the completeness of the catalogs is reduced. The merged catalog is reliable for the applications of different earthquake Prediction techniques