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.
Abstract: Despite the distinct features of the continuous wave (CW) Terahertz (THz) emitter using photomixing technique, it suffers from the relatively low radiation output power. Therefore, one of effective ways to improve the photomixer emitter performance was using nanodimensions electrodes inside the optical active region of the device. Due to the nanodimension sizes and good electrical conductivity of silver nanowires (Ag-NWs), they have been exploited as THz emitter electrodes. The excited surface plasmon polariton waves (SPPs) on the surface of nanowire enhances the incident excitation signal. Therefore, the photomixer based Ag-NW compared to conventional one significantly exhibits higher THz output signal. In thi
... Show MoreA modified Leslie-Gower predator-prey model with a Beddington-DeAngelis functional response is proposed and studied. The purpose is to examine the effects of fear and quadratic fixed effort harvesting on the system's dynamic behavior. The model's qualitative properties, such as local equilibria stability, permanence, and global stability, are examined. The analysis of local bifurcation has been studied. It is discovered that the system experiences a saddle-node bifurcation at the survival equilibrium point whereas a transcritical bifurcation occurs at the boundary equilibrium point. Additionally established are the prerequisites for Hopf bifurcation existence. Finally, using MATLAB, a numerical investigation is conducted to verify the va
... Show MoreThis study examines the impact of adopting International Financial Reporting Standards (IFRS) on the value of economic units. Given the global push toward standardization of financial reporting to enhance financial statement transparency, comparability, and reliability, this research seeks to understand the implications of these standards for economic valuation within a region characterized by its unique economic and regulatory challenges. A questionnaire was distributed to 86 Iraqi academics specializing in economics, accounting, and finance to collect their views on the impact of adopting international financial reporting standards. Through careful statistical analysis, the study concluded that applying international financial reporting s
... Show MoreThis study aims to apply the theory of "Text from Text and the Plus Dimension" in the analysis of the Prophetic discourse found in the section on the virtues of knowledge and scholars from Imam Sahih al-Bukhari's book. This section covers several topics, including the virtue of gathering for the sake of learning, the superiority of a scholar over a worshipper, the excellence of jurisprudence in the religion of Allah, the acquisition of knowledge through the passing away of scholars, the merit of inviting people to Allah, the continuing benefit of beneficial knowledge after a scholar's demise, the warning against seeking knowledge for purposes other than Allah, and the Prophet seeking refuge from knowledge tha
... Show MoreA field experiment was conducted at the experimental field of botanical garden, faculty of science, university of Baghdad, in order to study the effect of plant density on growth and yield of two local cultivars of sunflower (Sin Althieb and Shumose). The densities used were 4.4 and 8.8 plant/m2. The results showed difference between cultivars in their agronomic traits and their yields. There was a significant increase in plant height and leaf area index by increasing the plant density, while head diameter, number of seeds and leaf area decreased. But the most significant effect was the increasing in yield and biological yield by increasing the plant density. There was an increase by 72% and 58% in the yield and 79% an
... Show More
To identify the importance of the role of succession planning in developing human capital in organizations in light of the accelerating and dynamic events and changes in the work environment, and the research problem indicated the seriousness of employees retiring or leaving their positions for any reason and the extent of its impact on the organization in creating gaps in leadership and problems In managing the talent injection because there will be a shortage of talent, which in turn will affect the general performance of the business in the researched institute, so the importance of research appears in trying to present a set of solutions through which some of the problems facing the organization in quest
... Show MoreAbstract
The current research aims to identify the typical effect of Flower and Coscroft on expressive performance and the development of lateral thinking among literary fifth-grade students. To achieve the research objective, the researcher chose a sample of (90) female students from the fifth literary grade, with two experimental groups and a control group. The research groups are of six subjects. The research found that the two experimental groups have more expressive performance than the control group. Students of the first experimental group outperformed the students of the second experimental group in expressive performance and lateral thinking tests. In light of the findings of the research, the researcher
... Show MorePresent study was conducted in order to assess Slabiaat water quality by measuring some physical and chemical factors of river water, the study included a choice of three stations along of Slabiaat River in Samawa city, water samples collected a monthly during the period from September 2013 August 2014. The study involved measuring the Air & water temperatures, pH, Electrical conductivity, Total dissolved solids, Dissolved oxygen, Total hardness, calcium hardness, magnesium, turbidity, and some types of bacteria in River water. The study results showed that the values of air & water temperatures have ranged between (20.1-36.6)?C , (10-21.8) in Slabiaat River, respectively . pH values ranged between (6.6-8.7). Electrical conductivity in
... Show MoreIt is no secret to anyone that studying and investigating books of jurisprudence, despite their suffering, is a pleasure that cannot be compared to pleasure, and it has benefits and importance that cannot be limited and summed up, and it has great fruits that researchers and students of knowledge reap, as well as enriching libraries with jurisprudential material, after dusting them and taking them out to the light of libraries to be seen. Researchers and scholars, generation after generation, so that this nation can benefit from this pioneering intellectual and scientific product that was written for us by our first ancestors of working scholars who enriched human civilization with this scientific material, which has become a beacon guid
... Show More