The fouling depositions of crude oil stream were studied theoretically in a shell and tube heat exchanger to investigate the effect of depositions on the heat transfer process. The employed heat exchanger was with steam flowing in the inner tubes and crude oil in the shell at different velocities and bulk temperatures. It is assumed that fouling occurs only on the heated stream side (crude oil). The analysis was carried out for turbulent flow heat transfer conditions with wide range of Reynolds number, bulk temperature and time. Many previously proposed models for fouling resistance were employed to estimate a new model for fouling rate. It is found that the fouling rate and consequently the heat transfer coefficient were affected by Reynolds number, Prandtls number, film temperature, activation energy, and time.
The results obtained showed that fouling resistance decreased with the increasing of Reynolds number and Prandtls number, and increased with the increasing of film temperature and time. The analyses of results were compared with some experimental work and a reasonable agreement is attained.
The improvement of the mechanical soil characteristics of jet grouting technique is very attractive. The jet grouted soil cement columns in soft is a complicated issue because it depends on a number of factors such as, soil nature, mixture, influence among soil and grouting materials, jetting force of nozzle, jet grouting and water flow rate, rotation and lifting speed. This paper discusses the estimation of shear strength parameters of soil-cement column (soilcrete) in soft clayey soil based on the relationships between the unconfined compressive and split tensile strength for the soilcrete and the effect of the jet grouting and water pressure in the values of cohesion and internal f
The effect of water stress induced by using polyethylene glycol (PEG-6000) on germination of seeds and growth of seedlings of Silybum marianum was studied. Two concentrations of PEG were used to get two water stresses (-0.4 & -0.8 bar) as well as the control for comparison. The results showed a significant decrease (P<0.05) in germination ratio compared with the control. The ratio did not slow down to less than 50% which indicates the ability of the seeds to resist water stress to some extent. Also, a significant decrease (P<0.05) in the length of shoot and root was observed compared with the control. This plant showed
... Show MoreBackground: Chronic cigarette smoking is one of the major risk factors for coronary artery disease. However, it has additional cardiac adverse effects independent of coronary atherosclerosis. Patient and Methods: After informed consent and perm- ission from the review board of the hospital, 80 healthy subjects who were classified as smokers or non-smokers were included in the study. They were examined by standard echocardiography protocol which was followed by two-dimensional speckle tracking to assess the functions of the right ventricle. Results: The tricuspid annular plane systolic excursion (TAPSE) was significantly reduced in smokers as compared to non-smokers (P < 0.05). The tricuspid flow peak late diastolic velocity (A wave) was sig
... Show MoreIn this work an experimental study is performed to evaluate the thermal performance
of locally made closed loop solar hot water system using a shell and helical coiled tube
heat exchanger as a storage tank. Several measurements are taken include inlet and outlet
temperatures of both collectors and supply water and temperature distribution within the
storage tank. This is beside the water flow rate in both collectors and load cycle. The
main parameters of the system are obtained.
Products’ quality inspection is an important stage in every production route, in which the quality of the produced goods is estimated and compared with the desired specifications. With traditional inspection, the process rely on manual methods that generates various costs and large time consumption. On the contrary, today’s inspection systems that use modern techniques like computer vision, are more accurate and efficient. However, the amount of work needed to build a computer vision system based on classic techniques is relatively large, due to the issue of manually selecting and extracting features from digital images, which also produces labor costs for the system engineers. In this research, we pr
... Show MoreProducts’ quality inspection is an important stage in every production route, in which the quality of the produced goods is estimated and compared with the desired specifications. With traditional inspection, the process rely on manual methods that generates various costs and large time consumption. On the contrary, today’s inspection systems that use modern techniques like computer vision, are more accurate and efficient. However, the amount of work needed to build a computer vision system based on classic techniques is relatively large, due to the issue of manually selecting and extracting features from digital images, which also produces labor costs for the system engineers.
 
... Show MoreBackground: One of the drawbacks of vital teeth bleaching is color stability. The aim of the present study was to evaluate the effects of tea and tomato sauce on the color stability of bleached enamel in association with the application of MI Paste Plus (CPP-ACPF). Materials and Methods: Sixty enamel samples were bleached with 10% carbamide peroxide for two weeks then divided into three groups (A, B and C) of 20 samples each. After bleaching, the samples of each group were subdivided into two subgroups (n=10). While subgroups A1, B1 and C1 were kept in distilled water, A2, B2, and C2 were treated with MI Paste Plus. Then, the samples were immersed in different solutions as follow: A1 and A2 in distilled water (control); B1 and B2 in black
... Show MoreExperimental and numerical investigations of the centrifugal pump performance at non-cavitating and cavitating flow conditions were carried out in the present study. Experiments were performed by applying a vacuum to a closed-loop system to investigate the effects of the net positive suction head available (NPSHa), flow rate, water temperature and pump speed on the centrifugal pump performance. Accordingly, many of the important parameters concerning cavitation phenomenon were calculated. Also, the noise which is accompanied by cavitation was measured. Numerical analysis was implemented for two phase flow (the water and its vapor) using a 2-D simulation by ANSYS FLUENT software to investigate the internal flow of centrifugal pump under c
... Show MoreThe current research aims to identify the types and rates and the reasons for the crimes that are with the origin and sexual scattered deviation between the fabric of Iraqi society, which reticent about because of the culture of the community, where he offered a researcher investigator justice and tribal leaders and lawyers about proportion and the types and causes of crime is the origin of sexual deviance and finally a question asked a researcher in 1000 young lived their adolescence days of the former regime (1979-2003) from going to brothels researcher found that 920 people and 92% had gone to the house to practice adultery and that 70 of them, and by 7% had engaged in masturbation only and that 10 of them have not committed anything
... Show MoreCosmetic products contain variable amounts of nutrients that support microbial growth. Most contaminants in cosmetic products include bacteria such as Staphylococcus, Pseudomonas, Klebsiella, Achromobacter and Alcaligenes. Contaminated water is a likely source of organisms found in cosmetic products. Products such as shampoo, hand and body lotion, facial cleanser, and liquid soaps were analyzed. In this study, out of 60 cosmetic products analyzed, 26.4% were found to be contaminated. Most of the contamination was from bacteria and no fungal contamination was detected. The highest level o
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