Yanbu Journal of Engineering and Science (YJES)
Not a member yet
202 research outputs found
Sort by
STUDY OF THE THERMAL PROPERTIES AND MOLECULAR MASS OF POLYHYDROXYBUTYRATE PRODUCED BY RHODOCOCCUS EQUI
No full textIn the present study, the ability of Rhodococcus equi for polyhydroxyalkanoates (PHA) production was closely observed in the presence of crude palm kernel oil as a carbon source. Gas chromatography analysis proved that the biopolymer was a homopolymer that comprised of 38% polyhydroxybutyrate (PHB). The melting temperature (at 173°C) and glass transition temperature (at 2.79 °C) of PHA was determined using differential scanning calorimetry analysis, and the decomposition temperature (at 276°C) was determined by thermogravimetric analysis. The gel permeation chromatography revealed the average molecular weight (M) to be at 6.42 KD, the number average weight (M) at 373 KD, and the polydispersity (M/M) to be at 1.91. The present study demonstrated the use of an inexpensive substrate for PHB production by gram- positive bacteria that limited the study previously for the production of PHB polymer, which was analyzed by the polymer\u27s thermal properties and molecular mass
DEVELOPMENT OF THE REQUIRED TOPOGRAPHIC DATA FOR AN EFFECTIVE IRRIGATION SCHEME, USING SPACE TECHNOLOGIES CASE STUDY: NORTH OMDURMAN RURAL AREAS
No full textConsidering the growing negative environmental impacts all over the world and the deteriorating living standards in Sudan, this paper focuses on the authors\u27 contribution to an agricultural project that aims at participating in solving such problems in the study area. The study area, which is exploited by the local farmers, is located north of Omdurman at the western bank of the River Nile. The main objective of the entire project is to establish an irrigation scheme that provides cheaper, sufficient and constant water supply in order to reduce the irrigation cost and effort and increase productivity, leading to reducing the poverty level and improving the living standards. The contribution of the authors in this project is represented in the provision of the basic topographic information which represents a decisive factor for the design of the proposed irrigation scheme. The data used for getting the topographic information were space technology data such as Real time GPS readings, GPS Navigator readings, and Landsat ETM + image, as well as, digital ground survey data such as readings taken by the Total Station survey instrument at site. Using ERDAS Imagine 8.5, the ETM+ image was processed, interpreted to extract the necessary planimetric information. Using ArcGIS9.3 Geostatistical Analyst, the GPS - and Total Station readings were processed to obtain detailed information about the terrain. The effort made by the authors clearly revealed the important role of space technology to conduct the studies that assist in designing projects that reduce the negative environmental impacts and improving the living standards in the project area. The integration of the GIS facilities with this data represents an excellent addition, because it facilitates the presentation of the output in the form of dynamic maps accompanied by attributes of the different layers, beside the static maps. These layers are very useful for designing the detailed engineering activities required for designing the required irrigation scheme in a later stage
TURBULENCE MODELING IN STENOSED CAROTID ARTERIES USING CFD
No full textVarious numerical simulations of blood flow through stenosed (partially blocked) carotid arteries have been performed in the past but most of them have been limited to laminar flow. It has been reported in the literature that stenosis may promote disturbed flow causing transition from laminar to turbulence [1]. The studies on turbulence development in the post-stenotic regions are rare and have been performed by using only one or two turbulence models. In this work several turbulence models were used and validated against experimental data by using CFD (Computational Fluid Dynamics) package Fluent 6.1. A stenosed geometry of 75% area reduction was used in the simulation. It was found that SST (Shear Stress Transport) k-w model gave the best agreement with experimental data for Reynolds Number of 5000. We also analyzed the models at even lower Reynolds Number of 2000 and found that SST k-w model performed consistently better
STEAM INDUCED SHOCKWAVE INTERACTION WITH A SUBMERGED PLATE CONFIGURED AT A RANGE OF INCLINATIONS FROM VERTICAL
No full textInteraction of shock wave and the shear induced vortex across the steam-water layer has been vital in several transportation and chemical industrial processes. Experiments were conducted using a facility including a rectangular chamber, which housed a shock tube in it. Steam was injected into the tube to induce shock wave by bursting the Aluminum diaphragm disk and the shock wave surrounding by the steam-water shear layer induced vortex, exited the shock tube and struck the rectangular steel plate. PIV setup along with the pressure and acoustic emissions sensors were used to characterize the propagation and impingement of the shock wave on the plate as well as the behavior of the reflected shock wave and the vortex ring. In case of a vertical rectangular steel sheet stationed in front of the exit of the shock tube, the central part of the shock wave was found to interact with the central part of the vortex structure and the external part of the shock wave came into contact with the outer part of the vortex structure. Whereas in case of inclined sheet, the shockwave reflected from the sheet, came into collision with the rebound shockwave as well as with the lower portion of the vortex ring largely. However, with the further variation in the angle of inclination (i.e. 30o and larger) fromvertical axis, no further appreciable change was observed in the flow profile except the vortex ring interacted earlier with the rebounded shockwave in the lower region within the neighborhood of the plate than the interaction of the vortex ring with the rebounded shock wave in the upper region of the inclined plate. The pressure and acoustic emission measurements were symmetric with the vertical plate, however, the pressure data was asymmetric when the plate was inclined from vertical. When the angle of inclination changes to 30 degrees from the vertical, the flow becomes more asymmetric as the shockwave and the consequent vortices impinged on the surface of the plate much earlier than the 15 degrees’ inclination case
MODELING THE EFFECTS OF MOSQUE EXPLOSION ON PRAYERS
No full textMosques are temples for Muslims in which five prayers are held a day. The continuous escalation of terrorist threats in general and on mosques, in particular, necessitates the importance of protecting people and infrastructure from the burdens of malicious deliberate bombings. The consequences of the blast overburdens are catastrophic, including injuries, deaths, material and economic losses, and social upheaval. The current research employed numerical simulation to investigate the influence of an intentionally induced explosion in a confined, densely populated space on expected human casualties. The case study is a typical mosque building with an area of 600 square meters. Its maximum capacity is 720 prayers (Muslim worshipers), distributed in 12 rows, one behind the other. A detonation occurred as a result of a 1.15 kg TNT bomb exploding in the first row behind the Imam (leader of prayers). The time history of overpressure and speed was monitored at six different points. The four types of blast injuries, primary, tertiary, secondary, and quaternary, have been evaluated. The primary targets, the imam and prayers near the center of the explosion, are more likely to die from the tertiary blast injury. Prayers close to reflective walls, especially near the corners of the mosque, are at risk of death due to the primary blast injury. High winds have been found to cause more severe tertiary injuries than primary injuries resulting from blast overpressure. The information presented in this paper is useful for assessing post-blast damage and for estimating potential blast hazards from explosions. Appropriate design and provision of emergency exits can reduce the rates of physical injury and death resulting from explosions
Enhanced Photocatalytic Performance of Systematically Designed g-C\u3csub\u3e3\u3c/sub\u3eN\u3csub\u3e4\u3c/sub\u3e/rGO/TiO\u3csub\u3e2\u3c/sub\u3e Ternary Nanocomposite
No full textGraphitic carbon nitride (g-C3N4) has become a favorable photocatalyst due to its unique optoelectronic properties, however high recombination rate and low separation efficiency of the photogenerated charge carriers restrict their practical usage. To minimize the recombination rate, we synthesized a ternary nanocomposite, g-C3N4/rGO/TiO2 via a facile, simple, and cost-effective mechanochemistry technique. The ternary nanocomposite effectively degrades Rhodamine B (RhB) dye mainly due to higher visible light utilization and multi-step charge transfer mechanism. The optimal rGO plays an essential role in effective photocatalytic performance due to its unique electrical, large surface area, and optical properties. The synthesized nanocomposite degrades 80% RhB dye compared to pristine g-C3N4 and binary which degrades 39.6 and 64.8% respectively in 2h. This study showcases a simple, low-cost method for the effective degradation of dyes
Hough Transform based Deep Belief Network and Improved Homomorphic Encryption for Cloud Security based Intrusion Discovery
No full textThe enlarge development in information technology is cloud computing, which offers minimized infrastructure cost, lower maintenance, greater flexibility and scalability. Nowadays, the network security plays vital role in enterprises and organizations. The influence vulnerabilities were occurred due to attackers based on network configuration. Because of cloud and IoT growth, enlarge amount of data obtained from IoT sensor and devices are transmitted to cloud data centers. Several security issues like focused web servers in the cloud and information collection mishandling are faced by storage and cloud-based computing when offering us considerable convenience. For that reason, this article proposes a deep learning-based cloud security oriented intrusion discovery. Primarily, the input dataset is pre-processed by using normalization techniques followed by the features are selected using an Adaptive White Shark Optimization (AWSO) algorithm. The normal and intrusion data is classified by using Hough Transform based Deep Belief Network (HT-DBN) after that the sensitive data are secured with the help of an Improved Homomorphic Encryption (IHE) model. The simulation tool of MATLAB is been used to simulate the proposed implementation part and the experimental results outperformed the detection accuracy of 97% than other previous approaches
Application of Active Fault-Tolerant Control with Hardware Redundancy in Variable Frequency Drives of AC Induction Motors
No full textFault-tolerant control (FTC) techniques have the potential to significantly enhance the dependability of voltage source inverters (VSI) and are becoming popular. This study presents an innovative fault tolerance approach for designing a very dependable induction motor drive (IMD) that incorporates both analytical (active) and hardware redundancies. The created model aims to enhance fault tolerance against the current sensor, speed sensor, and IGBT switch failures in the inverter module. The Active Fault Tolerant Control System (AFTCS) has been applied to the speed sensor to detect any faults in the sensor. If a fault is detected, the system will replace the defective value with an estimated value for open loop speed estimation. This estimation is based on a flux estimation observer. The fault tolerance of the current sensors is designed such that to replace the defective value with the average value of the other two functional current sensors in the event of a failure in one sensor assuming that only one sensor gets faulty at a time. The Fault Detection and Isolation (FDI) unit is designed to rapidly identify and replace a defective switch with a backup redundant switch in the shortest possible timeframe. The stability and convergence of the observer is also proved using the Lyapunov theorem. The use of Markov chains in the reliability investigation further substantiated the system\u27s exceptional dependability. To evaluate the effectiveness of the suggested approach, a variable-speed induction motor with a power capacity of 1.1kW is constructed using MATLAB/Simulink. A 3-phase inverter and fault detector unit are implemented on an STM32-Nucleo-F103RB board with hardware-in-the-loop capability to validate the accuracy of the simulation results to highlight the robustness of the developed active fault-tolerant control. The simulation results coupled with the hardware-in-the-loop experiment demonstrate that the IM drive maintains its stability with little performance degradation in the events of faults in the speed and current sensors as well as inverter switches. Finally, a comparison with the existing literature was carried out to showcase the improved performance and heightened dependability of the proposed model
TRACING THE ROOTS OF CONSTRUCTION CONFLICTS: EXPLAINING PROBLEMS, PREFERENCES, AND PROCESS
No full textThe construction industry is continuously struggling to resolve the conflicts equitably and economically. Therefore, the present study aims to trace the roots of construction conflicts by explaining problems, preferences, and processes associated with the construction industry. Quantitative research design has been employed and 116 owners, constructors, consultants, and stakeholders were recruited because of their direct involvement in the construction industry. A questionnaire was distributed among the respondents to trace the problems, preferences, and processes associated with conflicts the construction industry. The results showed that that lack of communication and coordination, contract provisions, ambiguities, bid rigging, contracting classification system, unforeseen ground conditions, and discrepancies were major reasons of conflict. The study has concluded that productivity of construction industry is significantly influenced through the implementation of realistic schedule and plan for the construction project
VIBRATION ANALYSIS OF FUNCTIONALLY GRADIENT DENTAL IMPLANT
No full textA dental implant is considered as the best treatment when dealing with the loss of teeth. It gives beautiful results and can last longer than most of other treatments. Osseo- integration period is a critical period for implant stability. The material used for dental implants is one of the most important factors affecting the stability so using Functionally Gradient Material (FGM) can help improve the stability. In this study, several models for dental implants were analyzed by ANSYS 15.0 APDL. The FGM was considered in three models. The same materials, Ti-HA, were used in all of them but with different geometrical parameters. The natural frequency and mode shapes were extracted for all models and then the harmonic analysis was performed to study the frequency responses for the different models. It was noticed that all the extracted results for FGM vary between the two basic materials, and it is affected by the concentration of each. It is firmly believed that FGM is the future of dental implants due to its ability to design a specific material property for more stability