A pioneering idea for increasing the thermal performance of heat transfer fluids was to use ultrafine solid particles suspended in the base fluid. Nanofluids, synthesized by mixing solid nanometer sized particles at low concentrations with the base fluid, were used as a new heat transfer fluid and developed a remarkable effect on the thermophysical properties and heat transfer coefficient. For any nanofluid to be usable in heat transfer applications, the main concern is its long-term stability. The aim of this research is to investigate the effect of using four different surfactants (sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB), and gum Arabic (GA)), each with three different concentrations, and five ultrasonication times (15, 30, 60, 90, and 120 min) on the stability of water-based graphene nanoplatelets (GNPs) nanofluids. In addition, the viscosity and thermal conductivity of the highest stability samples were measured at different temperatures. For this aim, nineteen different nanofluids with 0.1 wt% concentration of GNPs were prepared via the two-step method. An ultrasonication probe was utilized to disperse the GNPs in distilled water. UV–vis spectrometry, zeta potential, average particle size, and Transmission Electron Microscopy (TEM) were helpful in evaluating the stability and characterizing the prepared nanofluids. TEM and zeta potential results were in agreement with the UV–vis measurements. The highest nanofluid stability was obtained at 60-min ultrasonication time. The prepared water-based pristine GNPs nanofluids were not stable, and the stability was improved with the addition of surfactants. The presence of SDBS, SDS, and CTAB surfactants in the nanofluids resulted in excessive foam. The best water-based GNPs nanofluid was selected in terms of better stability, higher thermal conductivity, and lower viscosity. From all the samples that were prepared in this research, the (1–1) SDBS–GNPs sample with 60-min ultrasonication showed the highest stability (82% relative concentration after 60 days), the second better enhancement in the thermal conductivity of the base fluid (8.36%), and nearly the lowest viscosity (7.4% higher than distilled water).
The study aims at showing the role of tax audit in Impact the quality of tax statements. Tax audit is one of the most important means used by tax management to identify taxable revenues in a just, fair manner. The quality of statements relies on the extent to which the information provided by taxpayers is true and accurate. Tax audit works is compatible with the strategy of increasing tax adherence and detecting non-adherence cases and penalizing those who commit such violations. The study reached a number of results and conclusions. One of the most important results is that tax audit helps improve the information content of the taxpayers tax statements. This leads to recalculating taxable incomes and re-fixing t
... Show MoreImage pattern classification is considered a significant step for image and video processing.Although various image pattern algorithms have been proposed so far that achieved adequate classification,achieving higher accuracy while reducing the computation time remains challenging to date. A robust imagepattern classification method is essential to obtain the desired accuracy. This method can be accuratelyclassify image blocks into plain, edge, and texture (PET) using an efficient feature extraction mechanism.Moreover, to date, most of the existing studies are focused on evaluating their methods based on specificorthogonal moments, which limits the understanding of their potential application to various DiscreteOrthogonal Moments (DOMs). The
... Show MoreAbstract The relative pronoun in Hebrew language is an important pronoun use anciently and recently, it developed and it's usage and meanings differed so, it was not confined to the particle "אֲשֶׁר" as a relative pronoun, but beside it appeared other pronouns giving the relative meaning. Hence, the topic of this research was on this basis through studying the relative pronouns in old and modern Hebrew, the way of using them and their connection with preposition particles, as well as studying the relative clause.
Credit card fraud has become an increasing problem due to the growing reliance on electronic payment systems and technological advances that have improved fraud techniques. Numerous financial institutions are looking for the best ways to leverage technological advancements to provide better services to their end users, and researchers used various protection methods to provide security and privacy for credit cards. Therefore, it is necessary to identify the challenges and the proposed solutions to address them. This review provides an overview of the most recent research on the detection of fraudulent credit card transactions to protect those transactions from tampering or improper use, which includes imbalance classes, c
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The achievement of agricultural development provide food security and to form a basis for economic growth and comprehensive social, requires a number of actions to overcome the obstacles and problems facing the development of this economic sector, to make it able to achieve food security and operation of the workforce, and reduce dependence on the outside in the provision of food peripherals, and so it is only available through the highest degree of efficiency and economic mobilization of resources, so most of the developed and developing countries alike seek to achieve sustainable agricultural development tobacco meet the food requirements and good jobs for c
... Show MoreThis research test the relationship and the effect of an explanatory variable transparency in the organizational reputation responder variable by senior management in the departments of the Ministry of Housing and Construction centrally funded, As well as come out among other recommendations contribute to the achievement of organizational reputation of the organizations surveyed. Given the importance of the research topic for the public sector and the community and the environment in which they operate researcher designed questionnaire containing (30) items, and collected data from (92) respondents, representing the research community (eight establishments) exclusively and comprehensively, relying descriptive analytic
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Number (42) 13 Ramadan 1436 H 30 June 2015
Abu Muhsin al-Thaqafi oscillating between disobedience and obedience
Research Summary
This research deals with the impact of Islam on the poetry of the veterans who realized ignorance and Islam
Persistent and shifting perspective in their poetry, especially those that talk about
Topics deprived of Islam, such as hair, for example. It is known that the description of alcohol is common in
Pre-Islamic poetry, and the Arabs were proud to drink it as proud of their heroism and Frosithm,
And drinking alcohol was associated with religious roots, they thought that the drinker acquires the attributes of God,
He can do the things that gods do, and humans can not. A
Wireless channels are typically much more noisy than wired links and subjected to fading due to multipath propagation which result in ISI and hence high error rate. Adaptive modulation is a powerful technique to improve the tradeoff between spectral efficiency and Bit Error Rate (BER). In order to adjust the transmission rate, channel state information (CSI) is required at the transmitter side.
In this paper the performance enhancement of using linear prediction along with channel estimation to track the channel variations and adaptive modulation were examined. The simulation results shows that the channel estimation is sufficient for low Doppler frequency shifts (<30 Hz), while channel prediction is much more suited at
... Show MoreMany cases of gravitational bullets are reported in developed and non-developed countries. However, few papers highlighted these cases in the literature. In our study, we present two cases of gravitational bullets that have an unusual coincidence in the injury characteristics through their ages, and gender, the site of the inlet.
Digital literacy is crucial in the modern workforce, where technology plays an integral role in daily operations. This abstract explores the significance of digital literacy in enhancing productivity, efficiency, and competitiveness in the workplace. Digital literacy encompasses the ability to use and navigate digital tools and platforms effectively, including software, applications, and online communication tools. In today's digital age, employers increasingly value candidates with strong digital skills, as they are better equipped to adapt to rapidly evolving technologies. This abstract highlights the importance of digital literacy in empowering employees to perform tasks more efficiently, collaborate seamlessly, and innovate effecti
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