Query: CuO

title: Predicting the efficiency of CuO/water nanofluid in heat pipe heat exchanger using neural network
abstract: In this study, the CuO/water nanofluid was used to increase the performance of heat pipe heat exchanger. The results showed that the rise in the input power of the heat pipe leads to increase the wall temperature of the pipe, whereas augmenting the concentration of nanoparticles leads to reduce the wall temperature and decrease the temperature difference between the evaporator and the condenser. Using the nanoparticles increases the thermal conductivity of the base fluid and minimizes the temperature gradient within it. Therefore, the thermal power of the heat pipe increases and its resistance decreases. Also, the results showed that with increasing evaporation filling ratio, the resistance reduces (by Fr 0.45) and then increases. Additionally, experimental data was compared with published data for the heat pipe in order to accurately evaluate the results obtained in this study. The results showed that the measured data are highly accurate. Also, the heat conductivity resistance equation was calculated based on the experimental data. In the next step, the model of neural networks was used to predict thermal performance, FR, the concentration of nanofluid and input power. The results showed that the network with an accuracy of 0.9938 is able to predict the heat transfer coefficient. A review of the predicted and experimental results for the verification part indicated that the residuals are scattered around the zero axis.

title: Engineering nanostructures of CuO based photocatalysts for water treatment: Current progress and future challenges
abstract: Nowadays, increasing extortions regarding environmental problems and energy scarcity have stuck the development and endurance of human society. The issue of inorganic and organic pollutants that exist in water from agricultural, domestic, and industrial activities has directed the development of advanced technologies to address the challenges of water scarcity efficiently. To solve this major issue, various scientists and researchers are looking for novel and effective technologies that can efficiently remove pollutants from wastewater. Nanoscale metal oxide materials have been proposed due to their distinctive size, physical and chemical properties along with promising applications. Cupric Oxide (CuO) is one of the most commonly used benchmark photocatalysts in photodegradation owing to the fact that they are cost effective, non toxic, and more efficient in absorption across a significant fraction of solar spectrum. In this review, we have summarized synthetic strategies of CuO fabrication, modification methods with applications for water treatment purposes. Moreover, an elaborative discussion on feasible strategies includes; binary and ternary heterojunction formation, Z scheme based photocatalytic system, incorporation of rare earth/transition metal ions as dopants, and carbonaceous materials serving as a support system. The mechanistic insight inferring photo induced charge separation and transfer, the functional reactive radical species involved in a photocatalytic reaction, have been successfully featured and examined. Finally, a conclusive remark regarding current studies and unresolved challenges related to CuO are put forth for future perspectives.

title: Engineering of Al/CuO Reactive Multilayer Thin Films for Tunable Initiation and Actuation
abstract: Sputter deposited Al/CuO multilayers represent the state of the art of energetic nanomaterials. As such, they offer an opportunity for tunable ignition and actuation because their theoretical energy densities are significantly higher than most conventional secondary explosives while being less sensitive to undesired initiation. Both the sensitivity and combustion properties (temperature, rate and products released) can be manipulated via the layering, reactant spacing and stoichiometry of the multilayer and, to a lesser extent, via interface engineering. In this article, we first describe the technology of deposition of Al/CuO multilayers focusing on direct current sputter deposition followed by a comprehensive review of the materials structural characteristics. Next, experimental and theoretical works performed on these reactive multilayered materials to date is presented in terms of methods used, the results acquired on ignition and combustion properties, and conclusions drawn. Emphasis is placed on several studies elucidating the fundamental processes that underlie propagating combustion reactions. We examine the influence of the ceiling temperature that traduces the multilayer disintegration when reaching high temperatures (e.g. vaporization temperatures) This paper provides a good support for engineers to safely propose Al/CuO multilayers structure to regulate the energy release rates and ignition threshold in order to manufacture high performance and tunable initiator devices.

title: Thermal and Hydraulic Performance of CuO/Water Nanofluids: A Review
abstract: This paper discusses the behaviour of different thermophysical properties of CuO water based nanofluids, including the thermal and hydraulic performance and pumping power. Different experimental and theoretical studies that investigated each property of CuO/water in terms of thermal and fluid mechanics are reviewed. Classical theories cannot describe the thermal conductivity and viscosity. The concentration, material, and size of nanoparticles have important roles in the heat transfer coefficient of CuO/water nanofluids. Thermal conductivity increases with large particle size, whereas viscosity increases with small particle size. The Nusselt number depends on the flow rate and volume fraction of nanoparticles. The causes for these behaviour are discussed. The magnitude of heat transfer rate is influenced by the use of CuO/water nanofluids. The use of CuO/water nanofluids has many issues and challenges that need to be classified through additional studies.

title: A Review on Green Synthesis of CuO Nanoparticles using Plant Extract and Evaluation of Antimicrobial Activity
abstract: In this review, we examine 'greener' routes to nanoparticles of copper oxides, an emphasis on recent developments. natural products or extracted from natural products. such as different plant extracts, have been used as reductants and as capping agents during synthesis. A very easy, efficient and environment friendly protocol was developed to synthesize green nanoparticles with an aqueous extract of the various plant. Nanoparticles and their compounds are known to exert a strong inhibitory and microbial activity on bacteria, viruses, and fungi. Green synthesis, characterization, and application of nanoparticles (NPs) are becoming an important challenge in nanotechnology. Green synthesis of nanoparticles is made in large quantities worldwide for a wide range of applications. This technique is very safe and environmentally friendly.

title: CuO nanostructures: Synthesis, characterization, growth mechanisms, fundamental properties, and applications
abstract: Nanoscale metal oxide materials have been attracting much attention because of their unique size and dimensionality dependent physical and chemical properties as well as promising applications as key components in micro/nanoscale devices. Cupric oxide (CuO) nanostructures are of particular interest because of their interesting properties and promising applications in batteries, supercapacitors, solar cells, gas sensors, bio sensors, nanofluid, catalysis, photodetectors, energetic materials, field emissions, superhydrophobic surfaces, and removal of arsenic and organic pollutants from waste water. This article presents a comprehensive review of recent synthetic methods along with associated synthesis mechanisms, characterization, fundamental properties, and promising applications of CuO nanostructures. The review begins with a description of the most common synthetic strategies, characterization, and associated synthesis mechanisms of CuO nanostructures. Then, it introduces the fundamental properties of CuO nanostructures, and the potential of these nanostructures as building blocks for future micro/nanoscale devices is discussed. Recent developments in the applications of various CuO nanostructures are also reviewed. Finally, several perspectives in terms of future research on CuO nanostructures are highlighted.

title: Investigating Heat Transfer and Skin Friction Using Water CuO Nanofluid between Eccentric Channels
abstract: The current paper presents the mixed convection of nanofluid flow between eccentric channels. The present research is the first simulation which studies the simultaneous effects of eccentricity and Richardson number on the nanofluid flow. Two different thermal boundary conditions are considered: case A (heat flux is applied on the inner channel) and case B (heat flux is employed on the outer channel) In this paper, convective heat transfer coefficient and skin friction coefficient are surveyed based on dimensionless eccentricity, nanoparticle concentration, boundary condition, and Richardson number. In case A and Richardson number of 0.1, the maximum and minimum convective heat transfer coefficient occur in concentricity and positive dimensionless eccentricity, respectively. Meanwhile, the highest and lowest skin friction coefficient on the inner channel happen, respectively, in concentricity and negative dimensionless eccentricity. Also, the convective heat transfer coefficient increases by the nanoparticle concentration increment from 0 to 0.04. Moreover, nanoparticle concentration does not affect the skin friction coefficient. In case B, convective heat transfer coefficient decreases by increasing the dimensionless eccentricity. Consequently, this article shows that applying heat flux on the channels, eccentricity and nanoparticle concentration are important parameters in the heat exchanger performance.

title: Effect of tungsten doping on the structural, morphological and bactericidal properties of nanostructured CuO
abstract: Copper oxide (CuO) has been broadly used in different technological and biological applications. However, based on the literature review, there are few reports describing the synthesis of tungsten doped copper oxide and its biological applications, although CuO and W (tungsten) based nanomaterials have been reportedly already synthesized. In this study we synthesized novel CuO and CuO/W (at.1% 2% and 4% nanoparticles and explored their tungsten content dependent bactericide activity. In order to obtain the materials, was used a co precipitation method which is of low cost. The synthesized materials were characterized by x ray diffraction (XRD) XRD results indicated that only the sample with at.1% of W presented pure Tenorite phase. Diffuse reflectance spectroscopy (DRS) allowed to obtain the band gap energy values; CuO/W (at.2% sample exhibited the minimum value of 2.62 eV. Grains sizes ranging from 39.78 to 53.47 nm were established through field emission scanning electronic microscopy (FE SEM) and these sizes were confirmed by transmission electron microscopy (TEM) Doping with W also influenced the morphology obtained in all cases. BET (Brunauer, Emmett, Teller) analysis allowed to establish an increase in specific surface area and pore size with W doping. The particle size was determined by dynamic light scattering (DLS) The bactericidal properties were tested using well diffusion method for Escherichia coli and Staphylococcus aureus bacteria. Bactericide response of CuO nanoparticles was improved by the inclusion of W dopant into the CuO structure, leading to an expansion in the inhibition zone for the CuO/W (at.1% sample; inhibition halo diameters were 1.5 and 12 mm for CuO and CuO/W (at.1% respectively. Hence, it was possible to infer the remarkable importance of the crystalline phase, morphology, particle size and specific superficial area of the CuO/W (at.1% nanoparticles in its bactericide performance. WO3 secondary phase affected the bactericide response of the materials obtained at at.2% and at.4% of tungsten content.

title: Review: Pengaruh Penambahan Massa CuO Terhadap Sifat Fotokatalitik Semikonduktor untuk Konversi CO2 menjadi Metanol.
abstract: Peningkatan kadar gas CO2 di atmosfer menyebabkan banyak kerugian pada kehidupan manusia. Salah satu solusi untuk mengurangi jumlah CO2 adalah dengan mengonversi gas CO2 menjadi metanol menggunakan proses fotokatalitik. CuO yang mempunyai respon dan kemampuan serap yang tinggi terhadap cahaya tampak karena memiliki celah pita sebesar 1,2 eV sering diaplikasikan sebagai fotokatalis. Tujuan dari paper review ini adalah menganalisis pengaruh penambahan CuO terhadap sifat fotokatalitik semikonduktor lainnya seperti ZnO, NaTaO3, TiO2, InVO4, dan graphene untuk konversi CO2 menjadi metanol. Penambahan CuO pada semikonduktor lainnya dengan jumlah sebesar 2 5 wt% CuO dapat meningkatkan sifat fotokatalitik dari semikonduktor tersebut, seperti menurunkan celah pita energi, terjadinya red shift pada absorption edge, menekan rekombinasi pasangan elektron hole, serta meningkatkan jumlah produksi metanol. Akan tetapi, saat penambahan CuO berlebih akan menurunkan sifat fotokatalitik semikonduktor karena CuO menutupi permukaan aktif dari semikonduktor lainnya. CuO/NaTaO3 menghasilkan metanol tertinggi dengan jumlah sebesar 1302.22 umol.gcat 1h 1 disebabkan karena nanopartikel CuO tersebar merata pada permukaan NaTaO3 dan NaTaO3 memiliki struktur perovskite sehingga elektron menjadi lebih aktif. Increased levels of CO2 gas in the atmosphere cause many problems to human life. One solution to reduce the amount of CO2 is to convert it to methanol using a photocatalytic process. CuO which has a high response and absorption ability to visible light because it has a band gap of 1.2 eV is often applied as a photocatalyst. The purpose of this review paper is to analyze the effect of adding CuO to the photocatalytic properties of other semiconductors such as ZnO, NaTaO3, TiO2, InVO4, and graphene for the conversion of CO2 to methanol. Addition of CuO to other semiconductors with 2 to 5 wt% CuO can improve the photocatalytic properties of the semiconductor, such as decreasing the band gap energy, red shift on the absorption edge, suppressing recombination of electron and hole pairs, and increasing the amount of methanol production. However, when adding excess CuO will reduce the photocatalytic properties of the semiconductor because CuO covers the active surface of other semiconductors. CuO/NaTaO3 produced the highest methanol with an amount of 1302.22 umolg.cat 1h 1 because CuO nanoparticles were spread evenly to the surface of NaTaO3 and NaTaO3 has perovskite structure so that electrons become more active.

title: An overview on characterization of CuO based nano lubricant
abstract: This paper provides an overview on 'synthesis and characterization of nanolubricant' Nowadays, nano lubricant is noticed as an emerging topic that has great potential to enhance the efficiency and durability of base fluid. Nano size of the particle makes it a futuristic material when compared to ordinary scale material and hence shows a remarkable growth in the last three decades. The changes occur in tribological properties after addition of CuO nano particle in base engine oil has been studied. It also includes distinctive explanation of nano particle depends on morphology and surface charge. The various characterization techniques and synthesis approach have been discussed.