This paper reports a numerical study of flow behaviors and natural convection heat transfer characteristics in an inclined open-ended square cavity filled with air. The cavity is formed by adiabatic top and bottom walls and partially heated vertical wall facing the opening. Governing equations in vorticity-stream function form are discretized via finite-difference method and are solved numerically by iterative successive under relaxation (SUR) technique. A computer program to solve mathematical model has been developed and written as a code for MATLAB software. Results in the form of streamlines, isotherms, and average Nusselt number, are obtained for a wide range of Rayleigh numbers 103-106 with Prandtl number 0.71 (air) , inclination angles measured from the horizontal direction 0º-60º , dimensionless lengths of the active part 0.4-1 ,and different locations of the thermally active part at the vertical wall. The Results show that heat transfer rate is high when the length of the active part is increased or the active part is located at middle of vertical wall. Further, the heat transfer rate is poor as inclination angle is increased.
Symmetric cryptography forms the backbone of secure data communication and storage by relying on the strength and randomness of cryptographic keys. This increases complexity, enhances cryptographic systems' overall robustness, and is immune to various attacks. The present work proposes a hybrid model based on the Latin square matrix (LSM) and subtractive random number generator (SRNG) algorithms for producing random keys. The hybrid model enhances the security of the cipher key against different attacks and increases the degree of diffusion. Different key lengths can also be generated based on the algorithm without compromising security. It comprises two phases. The first phase generates a seed value that depends on producing a rand
... Show MoreThe Accommodation industry in Iraq suffers from many problems, especially after 2003, when the Accommodation industry was exposed to many crises due to the security and political situation in Iraq, which negatively affected the administrative operations inside the industry and created many problems, the most important of which are deterioration, high costs and poor performance, so some hotel administrations sought To find alternative solutions that help in the advancement of hotels, one of the proposals is to go to technology, as technology is currently one of the most important solutions to solve large complex problems, as the world has turned to automation to solve complex problems such as increasing production, reducing costs, and rai
... Show MoreNatural bitumen (NB) is a highly precious material and has drawn increasing attention due to its unique properties, especially since it is available in large quantities and has been used in limited fields. In this research, the exploitation of NB from sulfur springs as an alternative energy resource in the production of asphalt pavement is evaluated. It can be concluded from the experimental results that the chemical composition and surface morphology of NB samples are different from those of base asphalt. Besides, the rheological properties of virgin NB are not sufficient for paving work. To overcome this obstacle, NB from five different springs is modified with limestone filler (LSF) to enhance its properties. LSF is a natural material an
... Show MoreThe aim of this study is to recognize the influence of model of active thinking in achievement ofeighth grade students andtheir visual thinking in science.The finds of this research show the superiority students of the experimental group who studied the science material by using the active thinking model on the students of the control group who studied by usual method, in the achievement test. Also the finds show that the students of the experimental group are more successful than students of control group in the test of visual thinking, so the two null hypotheses have been rejected. In light of the results of the research, numbers of recommendations were made.
This study was conducted to describe a protocol for the callus establishing culture of Lavandula angustifolia plant and estimating their content of volatile oil. The quantity of volatile oil callus tissues was compared with that of leaves production. Callus was induced from leaf explants on Murashige and Skoog medium (MS) supplemented with Naphthalene acetic acid (NAA) and Benzyl adenine (BA) in different concentrations. Maximum callus fresh weight was obtained in the combination of 10 mg/L BA and 3 mg/L NAA which reached 18 g after four weeks. The results of this work showed that the quantity of volatile oil from the highest fresh weight callus was 6 ml compared with quantity of 18g of leaves which gave 0.5 ml. Volatile o
... Show MoreThe effects of T-shaped fins on the improvement of phase change materials (PCM) melting are numerically investigated in vertical triple-tube storage containment. The PCM is held in the middle pipe of a triple-pipe heat exchanger while the heat transfer fluid flows through the internal and external pipes. The dimension effects of the T-shaped fins on the melting process of the PCM are investigated to determine the optimum case. Results indicate that while using T-shaped fins improves the melting performance of the PCM, the improvement potential is mainly governed by the fin’s body rather than the head. Hence, the proposed T-shaped fin did not noticeably improve melting at the bottom of the PCM domain; additionally, a flat fin is ad
... Show MoreKlebsiella infections in the oral cavities of both humans and dogs have been increasingly reported and are associated with various buccal infections, as well as systemic infections. These infections appear to be rising particularly among pets and their owners, suggesting a possible bidirectional transmission between humans and dogs. Therefore, this study aimed to investigate the potential link of mixed infections involving Klebsiella pneumoniae and Enterococcus spp. Buccal cavity samples were collected from humans (n = 25) and dogs (n = 25). Samples were initially enriched in tryptic soy broth and subsequently cultured on tryptic soy agar, MacConkey agar, and blood agar. All isolates were identified using the VITEK 2 system, and eight selec
... Show MoreWe study the physics of flow due to the interaction between a viscous dipole and boundaries that permit slip. This includes partial and free slip, and interactions near corners. The problem is investigated by using a two relaxation time lattice Boltzmann equation with moment-based boundary conditions. Navier-slip conditions, which involve gradients of the velocity, are formulated and applied locally. The implementation of free-slip conditions with the moment-based approach is discussed. Collision angles of 0°, 30°, and 45° are investigated. Stable simulations are shown for Reynolds numbers between 625 and 10 000 and various slip lengths. Vorticity generation on the wall is shown to be affected by slip length, angle of incidence,
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