Yanbu Journal of Engineering and Science (YJES)
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Capuchin search algorithm based task scheduling in cloud computing environment
No full textCloud computing is mathematical process that provides more power and flexibility in computing infrastructure. Cloud computing provides internet services using a network of remote services. The core service for any environment is the best business plan that supports better quality of service (QoS). Task scheduling in the cloud is a key issue that needs to be addressed to improve system performance and high customer satisfaction. The task scheduling affects the exact time of operation and the cost of using the system. In this paper, we propose a capuchin search algorithm based task scheduling (CSTS) in cloud computing environment. In CSTS method, first we introduce an improved cuttlefish optimization (ICFO) algorithm for task clustering which groups user task into two set as normal and emergency task. Then, we develop a modified capuchin search (MCS) algorithm for priority based optimal task scheduling which minimize makespan and improve resource utilization. Finally, the simulation results of proposed CSTS method is compared with the existing state-of-art methods in terms of makespan, execution time, deadline violation rate and resource utilization
Comparative analysis of water cooler for different working fluids: Energy and exergy approach
No full textEnhancing the performance of traditional vapor compression cooling cycles is an important aspect in the quest to minimize global energy consumption, to own sustainable energy systems soon, and to preserve the environment. This study performed a comparative analysis of the performance of a water cooler with different working fluids to replace R143a and improve system performance. A mathematical model derived from energy and exergy analysis is developed for the evaluation of the effect of operating conditions on the system COP, exergetic losses, and exergetic efficiency. The evaluation has been conducted for evaporation and condensation temperatures ranging between -30°C to 15°C and 25°C to 55°C, respectively. Results showed that the cycle with R510A has the maximum COP. The average system COP with R510A, RE170, and R152a are 19.54%, 13.53%, and 9.36 % higher than that with R134a, respectively. The highest value of exergy loss takes place in the compressor. At different working fluids, exergy losses decrease as evaporation temperatures increase and condensation temperatures decrease. The system with R510A has the minimum exergy losses. The average exergy losses for systems with R510A, RE170, and R152a are 34.62%, 28.33%, and 18.64% lower than that of R134a, respectively. The system with R510A has higher exergy efficiency and R134a has the minimum values of exergy efficiency. Generally, the water cooler provided better performance with R510A and RE170 than with R152a and R134a. Therefore, R510A can be considered as the best replacement for R134a and R152a
Design and synthesis of Ag NPs/Cellulose nanofiber-starch nano-bio composites for packaging applications
No full textAddressing problems due to conventional plastics requires a comprehensive approach involving waste reduction, improved waste management practices, and the development of sustainable alternatives to conventional plastics. In this study, a system was designed that can decorate cellulose nanofiber with silver nanoparticles (AgNP) and then used as a reinforcing agent in thermoplastic starch matrix. The composites were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM) and transport properties. The morphology and chemical modification of cellulose nanomaterials with silver nanoparticles were confirmed by FESEM, TEM and FTIR and the results indicated proper adhesion of silver nanoparticles in cellulose nanofiber. The addition of AgNP decorated cellulose nanofiber on thermoplastic starch matrix could effectively reduce cracks and pores and improves the overall performance of nanocomposite films. The unique properties of starch nanoparticles make them a promising candidate for diverse applications, showcasing their potential as a sustainable and versatile nanomaterial
Effect of Al\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e Passivation on Structured Si/PEDOT:PSS Hybrid Solar Cell
No full textRecently, silicon/organic heterojunction solar cells (HSCs) attain great attention because of its attractive characteristics such as rationally high efficiency, low cost, and simple device fabrication technique. However, inferior junction conformity between structured Si and PEDOT: PSS still remains a great challenge. Here, a superior, conformal, and uniform Al2O3 thin layer is deposited on structured pyramid n-Si wafer to enhance the front junction conformity using atomic layer deposition (ALD) technique. The deposited Al2O3 thin layer provides better wettability of PEDOT:PSS compared to native oxide, which minimizes pores, and pin-hole density usually occurs in spin-coating process. Additionally, Al2O3 thin layer acts as an electron-blocking and hole-transporting layer, resulting in an effective charge separation as well as transport, which boosts the power conversion efficiency. The interface-modified device demonstrates a high open-circuit voltage of 0.612 V as well as a fill factor of 70.7%, leading to a stable efficiency of 14.3% for structural n-Si/PEDOT: PSS HSCs
Harris Hawks Approach for Distinct Economic Dispatch Problems
No full textIn this article, a nature inspired optimization approach is suggested, which is named Harris Hawks Approach (HHA). The prime inspiration of HHA is the mutual attitude and chasing way of Harris\u27 hawks in kind named surprise swoop. In this brilliant drawing, diverse hawks swoop victim cooperatively from distinct ways in an endeavor to startle it. Harris hawks can detect a sort of chasing paradigms rely on the spirited nature of scenarios and escaping styles of the victim. HHA is developed for handling the Economic Dispatch (ED) process. Since the ED is a non-linear, complex and obliged optimization process, its prime target is to lower the net generation cost while achieving the inequality and equality restrictions of the studie system. To prove the capabilities of the developed HHA, several test systems including 6, 13, 40 and 10 units have been implemented and tested for solving various ED problems. The simulation results clarify the potency of the HHA compared with other approaches illustrated recently in literature
THE EFFICIENCY OF USING STEEL FIBERS TAKEN FROM OLD TIRES IN POLYMER CONCRETE COMPARED WITH IMPORTED FIBERS
No full textThis research includes a study of the effect of adding steel fibers extracted from old tires from cars (which are now available in abundance in Iraq) to polymer concrete. The efficiency of these fibers is compared with imported fibers. These two types of fibers were added with percentages of concrete volumes. These percentages were (1%), (1.5%) and (2.0%). Reference concrete mix without fibers was also made for comparative purposes. Results proved that adding steel fibers with these percentages, regardless of their source, lead to improvements in all tested properties of concretes in comparison to concrete samples without fibers. The results were compared with conventional concrete. It was observed that concrete specimens with steelfiber (regardless of its type) increased its compressive strength approximately by 3-15%, its splitting tensile strength by 30-70%, and its flexural strength by 39-91%. The improvement in flexural and splitting tensile strengths appeared more clearly. However, the results did not show any clear differences regarding the impact of either type of fiber (extracted and imported) meaning that the use of this fiber (from old tires) is more economical, in addition to being a solution to the problems caused by waste tires and a contribution in the protection of the environment and the society
INVESTIGATING THE INFLUENCE OF POLYDIMETHYLSILOXANE (PDMS) CROSSLINKING CONTENT ON MEMBRANE SELECTIVITY
No full textPolymer crosslinking has significant importance in the relevant retrofitting of the microstructure of polymer network in terms of polymer swelling, membrane performance and its stability. This research focused on investigating the sorption influence on membrane selectivity in terms of measuring swelling of polydimethylsiloxane (PDMS) at varying polymer crosslinking in alcohol/water solutions. ATR-FTIR spectra for different crosslinked PDMS were obtained using Nicolet FTIR Spectrometer, and solvent concentration was determined by refractometer. The experimental results transpired that swelling degree decreased with increasing crosslinking content, which led to a more rigid polymer network structure resulting in less free volume as well as reduced absorbed liquid in the polymer. The addition of crosslinker resulted in the reduction of PDMS hydrophobicity influencing the sorption of alcohol into the polymer. It was found that PDMS at all crosslinking contents was selective towards ethanol and isopropanol and that addition of the crosslinker at concentrations at or below 10% led to the existence of vinyl and/or Si-H groups in the network. The sorption coefficient for isopropanol was also found to be higher than that of ethanol at all crosslinking contents, with increasing crosslinking content resulted in increased sorption coefficient
DESIGN AND IMPLEMENTATION OF A MUSEUM SECURITY SYSTEM USING AN IR PROXIMITY ANTENNA
No full textThis paper highlights the drawbacks of the current security systems for museums and bankos. Accordingly, it introduces a design of an efficient and simple security system. The system is based on the fact that any human being radiates an infrared radiation. The proposed security system consists of antenna, Programmable System on Chip (PSoC), a Silicon Controlled Rectifier (SCR), and an alarm. If any human being approached valuable protected item, the antenna collects the infrared radiation and gives an analogue output equivalent to this radiation to the PSoC where it converts the analogue to a digital and compare it with the preset threshold level. If the level of the collected signal is greater than the threshold level, PSoC feeds logic level high (five volts) to the SCR. The output of the SCR will activate a load which could be a buzzer or Light Emitting Diode (LED) to give either a sound or a light alarm, respectively. The paper describes the design and implementation of the proximity alarm system. The system is tested and found to be working successfully. Advantages of the proposed security system are: immediate response, no apparent components, no interference with daily business, and all-the-time activation
LOCALIZATION PHENOMINA AND FRACTURE ENERGY OF CONCRETE AT EARLY AGES
No full textSeveral experimental studies have been done long time ago to calculate the fracture energy of concrete [2, 6]. Most of these studies neglected the loss of energy due to the frictional process in the mechanism of experimental set up. All these studies have used the indirect tensile testing method, as a suitable approach for determining the fracture energy of concrete of mature age [3, 7]. However all these experimental studies have not investigated the crack or the localization process of young age concrete yet. So, to study the fracture and localization process at early ages of concrete, this experimental investigation study is done. Fracture energy for concrete at early ages is estimated experimentally considering the weather of Kingdom of Saudi Arabia. The specimens at early age are tested to calculate the fracture energy of concrete using a direct tension test, taking into consideration the loss of energy due to the frictional process in the mechanism of experimental set up. Also the crack localization is considered during the experiment, as dealing with the localized fracture. In this experimental work, the measurements reach to the post peak softening branch of concrete using the direct tension. The results show that there is a fairly good agreement between the experimental results and the numerical output using the Modified Lattice Model [9,10,11]
EFFICIENT METAMATERIAL PARABOLIC OPTICAL TAP DESIGN
No full textA metamaterial parabolic tap design is proposed and investigated; the tap has a metamaterial filling, it is designed for producing an efficient tapping where the subwavelength focusing exists. The design shows a high efficiency (power/physical dimensions) compared to a metamaterial rectangular tap design and to a natural material parabolic design. For comparison, the natural material parabolic design provides only 1% of the guided power while the output of the metamaterial parabolic design is 26%. For the same length and depth, the metamaterial rectangular tap design produces 8%. Moreover, it is noticed that the scattering around the tap is significantly low