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 research sheds light on the subject of phraseology as an important field to present metaphysical issues with contemporary scientific discourse. (Primary psychology) It does not apply with the reality of this science and therefore some tried to call it other names such as (Alsai), a unit of measurement of energy activity of things and assets. It was also called metaphysics or metaphysics, but it eventually settled on parapsychology. We try to win Islam and religious concepts with contemporary scientific discourse. The researcher discussed issues that modern science was unable to comprehend and interpreted. He used these subjects to prove the truths of religion and faith. Modern times because the whole universe miracles or as Imam Ghaz
... Show MoreThis paper presents the concepts of prepaths, paths, and cycles in α-topological spaces and studies them in orderable spaces. Also, many relationships are proved with their equivalences using some properties in topological spaces like compactness and locally connectedness.
The subject of the tagged research (becoming and integration of the film in postmodern cinema) is summarized by studying the transformations and complementarity of the film in light of the emergence of the concern of postmodernism. Then the need for it, as well as the objectives of the research and clarify its limits, as well as its importance. Then the transition to the theoretical framework, which included two sections, the first topic was entitled: Postmodern Cinema Formation and Completion, while the second topic was entitled: Paradox in Postmodern Film.
After completing the theoretical aspect, the research concluded with a number of theoretical framework indicators that were adopted as a tool for analyzing the sample, then th
... Show MoreA study Andalusia woman in shade society Arabic Islamic conservative on social customs in respect instructions in the different cover and tongue and not reveal beautiful woman because she is development the honor conscience in the society and she is respect not mix with the men about fall what he said the law Islamic and belief that the Andalusian people prince Husham days ago and he entry dependence to the mawta book. But the Andalusia woman was having the freedom and boasting and the greatness and beautiful and not respected factions from Andalusia woman instruction religion fewness commitment in the tradition Arabian and Islamic her promiscuity her promiscuity in the Spanish society that it is different habits and traditions with soci
... Show MoreDiesel generators is widely used in Iraq for the purpose of maintaining electric power demand. Large number of operators engaged in this work encounters high level of noise generated by back pack type diesel generators used for this purpose. High level of noise exposure gives different kinds of ill effect on human operators. Exact nature of deteriorated work performance is not known., in present research , quastionaire was adsministered 86 repondents in Baghdad city were exposured to wide range of noise level (80-110) dB(A) with different ages and they have different skill discretion levels. Noise levels A-weigthed decibles dB(A) were measured over 8 weeks two times aday during the 2019 summer using a sound level meter.For predicting the wo
... Show MoreLow back pain a major causes of morbidity throughout the world and it is a most debilitating condition ,and can lead to decreased physical function ,compromised quality of life, and psychological distress. Obesity is nowadays a pandemic condition. Obese subjects are commonly characterized by musculoskeletal disorders and particularly by non-specific LBP. However, the relationship between obesity and LBP remain to date unsupported by objective measurements of mechanical behavior of spine and it is morphology in obese subjects. Key words: obesity, low back pain,
In mammals, the kidneys originate in an embryo from the mesoderm through three excretory organs, namely: Pronephros, Mesonephros, and Metanephros. After the formation of Metanephros is completed, the kidneys begin to form nephrogenesis through mesenchymal cells located at the tip of the ureteric bud, that contribute in the formation of glomerulus and Renal tubules. The stages of glomerulus formation in the embryo of albino mice at the age of 14 to 19 days of gestation were studied. It was obtained after the sacrifice of the expectant mother and the kidneys were excised from the embryos and fixed using Aqueous Bouin's solution, Microscopic slices with a thick
... Show Moreتم تقييم المعرفة والوعي تجاه داء الكريبتوسبوريديوس في هذه الدراسة خلال الفترة من أبريل 2009 حتى يونيو 2011 ، من بين 188 شخصًا من كلا الجنسين تم تقسيمهم إلى مجموعات ومجموعات فرعية مختلفة على النحو التالي المجموعة 1: تشمل 48 طبيبًا من مختلف المستشفيات والرعاية الصحية الأولية مراكز في بغداد تم تقسيم هذه المجموعة إلى 30 طبيبًا متخصصًا و 18 طبيبًا ممارسًا عامًا. المجموعة الثانية: تضم 45 عضو هيئة تدريس من قسم الأحياء ، قس
... Show MoreIn this paper we show that if ? Xi is monotonically T2-space then each Xi is monotonically T2-space, too. Moreover, we show that if ? Xi is monotonically normal space then each Xi is monotonically normal space, too. Among these results we give a new proof to show that the monotonically T2-space property and monotonically normal space property are hereditary property and topologically property and give an example of T2-space but not monotonically T2-space.
RMK Al-Zaid, AT Al-Musawi, SJ Mohammad