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).
Abstract
Praise be to God, Lord of the Worlds, and prayers and peace be upon the most honorable of creation, Muhammad, whom God sent as a mercy to the worlds, and his infallible, pure, and pure family, and his faithful companions
I did not find anyone who studied stylistic structures except for one study, which is (The Literature of Imam Al-Jawad (peace be upon him), a stylistic study by the student Mina Reda Kazem, a master’s thesis), and it did not address the Hadi and the military men (peace be upon them) as the text of those texts. Coherently complementing each other.
I decided to stand by this heritage as a single text in a uniform period of time approximately from the year 195-260 AH, some
... Show MoreResearch title: Ruling on abortion in Sharia and law.
The importance of research: Projection is of great importance because it touches the life of a living being who enjoys human qualities. However, this organism often wastes its rights and does not protect its human beings. These souls are lost in millions by the sake of casual desire or hidden desire.
The research plan: The research dealt with an introductory topic, four topics, and in each topic there are demands, branches, and a conclusion.
The most important findings of the study: The ruling on aborting the fetus in the Sharia is only permissible (and the necessity is valued at its va
... Show MorePrecarity means the lack of social and economic networks; a considerable exposure to danger and harm. Minority groups are precariat for they lack rights and full citizenship. Precarity is related, states Judith Butler, with the individual’s performativity, and his ability to perform his gender role. Toni Morrison continually goes to past to retell the history of African Americans. The issues of race, gender and national identity are recurrent in her work. Reading her book Home (2012) evokes the idea of precarity and performativity since the two main characters, Frank and Cee are precarious characters that fail to perform their gender role properly, and eventually are exposed to hazard and harm. This research displays how African American
... Show MoreIn this paper, for the first time we introduce a new four-parameter model called the Gumbel- Pareto distribution by using the T-X method. We obtain some of its mathematical properties. Some structural properties of the new distribution are studied. The method of maximum likelihood is used for estimating the model parameters. Numerical illustration and an application to a real data set are given to show the flexibility and potentiality of the new model.
Background: Genetic factors play an important role in susceptibility to Guillain Barre' syndrome. Human leukocyte antigen (HLA) as part of immune system has a role in the disease process.Aim of the study: to assess the relationship between HLA-A alleles with Guillain Barre' syndrome (GBS) compared with a healthy control group using PCR-SSOP method.Type of the study: Cross-sectional study.Patients and methods:Patient's group consisted of 30 Iraqi Arab Muslims patients with Guillain Barre' syndrome that consulted the Neurological department in Neurosciences Hospital between January-2013 to January- 2014 were genotyped for HLA-A alleles. A control group consisted of 30 healthy volunteers among the staff of AL-Kindi College of Medicine that
... Show MoreThis research concluded that after what has been presented an analysis of the topics that the process of measuring the level of development and then the development gap is the need to assess the results to set policy and to formulate plans and goals, and to see the development priorities of the place or a particular sector. The purely economic development led to negative effects on the spatial scale and the most important of these effects arise multidimensional social and urban development gaps as well as the economic dimension. So it must exceed the concept of economic framework, to include all dimensions of development spatially and sectorally to provide correct and clear base for planners and development policies and strategies for de
... Show MoreBackground: Neonatal Septicemia (NNS) is generalized microbial symptomatic infection during the first 28 days of life.It>s the most serious complication in Neonatal Intensive Care Units (NICU) that demand urgent diagnosis and accurate treatment.Objective: To reveal the relationship of neonatal septicemia with birth weight (one of the neonatal risk factors).Patients and Methods: Blood sample was obtained from 76 neonates aged 1 hour-28 days who were diagnosed clinically (poor feeding, respiratory distress, fever, hypothermia, gastrointestinal and/or central nervous system symptoms)and bacteriologically to have neonatal septicemia.Results:One of the most important neonatal factor predisposing to infection is low birth weight, signi
... Show MoreHere, we synthesized three new blended ligand complexes of chromium (III), iron (III), and lanthanum (III) ions with a Schiff base made from the condensation of [o-aminophenol and 2-hydroxyacetophenone in the presence of concentrated sulphoric acid (HL1)] as a primary ligand and o-nitroaniline (L2) as a secondary. The Schiff base and its dual ligand chelate were characterized using several spectroscopic studies, IR, 1HNMR, electronic and mass spectra, in addition to elemental analyses, molar conductivity measurements, and magnetic moments. The spectroscopic and analytical outcomes confirmed the formation of the chelates in a 1:1:1(L1: M: L2) ratio. Similarly, an octahedral structure became counseled for all chelates.
Postcolonial theory deals with the effects of colonization on the colonized societies and their cultures. It examines the complex relationship between the colonized and the colonizer, and it represents the textual reactions that deal directly with such an issue. It is also a literary critique to texts that carry racist or colonial implications. The emergence of postcolonial theory as an aspect of literary criticism represents a shift in the focus of studies regarding the relation between the western and non-western worlds.
In contemporary theoretical discourse, Edward Said has been among the more influential postcolonial critics to draw attention to the centrality of imperialism in Western culture. Said’s work has provided a th
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