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1 – 10 of 92Marjan Goodarzi, Saeed Javid, Ali Sajadifar, Mehdi Nojoomizadeh, Seyed Hossein Motaharipour, Quang-Vu Bach and Arash Karimipour
With respect to two new subjects, i.e. nanofluids and microchannels, in heat transfer systems and modern techniques used for building them, this paper aims to study on effect of…
Abstract
Purpose
With respect to two new subjects, i.e. nanofluids and microchannels, in heat transfer systems and modern techniques used for building them, this paper aims to study on effect of using aluminum oxide nanoparticles in non-Newtonian fluid of aqueous solution of carboxy-methyl cellulose in microtube and through application of different slip coefficients to achieve various qualities on surface of microtube.
Design/methodology/approach
Simultaneously, the effect of presence of nanoparticles and phenomenon of slip and temperature jump has been explored in non-Newtonian nanofluid in this essay. The assumption of homogeneity of nanofluid and fixed temperature of wall in microtube has been used in modeling processes.
Findings
The results have been presented as diagrams of velocity, temperature and Nusselt Number and the investigations have indicated that addition of nanoparticles to the base fluid and increase in microtube slip coefficient might improve rate of heat transfer in microtube.
Originality/value
The flow of non-Newtonian nanofluid of aqueous solution of carboxy methyl cellulose-aluminum oxide has been determined in a microtube for the first time.
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The synthesis of a series of disperse dyes containing a carboxy group is described. The dyes were applied to polyester, wool and wool-polyester blend fabrics and their dyeing and…
Abstract
The synthesis of a series of disperse dyes containing a carboxy group is described. The dyes were applied to polyester, wool and wool-polyester blend fabrics and their dyeing and fastness properties evaluated. The levelling and fastness properties of all dyed samples meet commercial requirements. The effects of the carboxy group on the colour, dyeing and fastness properties ofthe dyes are discussed.
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Khaled Mostafa and Azza El-Sanabary
The novelty addressed here is undertaken by using tailor-made and fully characterized starch nanoparticles (SNPs) having a particle size ranging from 80 to 100 nm with a larger…
Abstract
Purpose
The novelty addressed here is undertaken by using tailor-made and fully characterized starch nanoparticles (SNPs) having a particle size ranging from 80 to 100 nm with a larger surface area, biodegradability and high reactivity as a starting substrate for cadmium ions and basic dye removal from wastewater effluent. This was done via carboxylation of SNPs with citric acid via esterification reaction using the dry preparation technique, in which a simple, energy-safe and sustainable process concerning a small amount of water, energy and toxic chemicals was used. The obtained adsorbent is designated as cross-linked esterified starch nanoparticles (CESNPs).
Design/methodology/approach
The batch technique was used to determine the CESNPs adsorption capacity, whereas atomic adsorption spectrometry was used to determine the residual cadmium ions concentration in the filtrate before and after adsorption. Different factors affecting adsorption were examined concerning pH, contact time, adsorbent dose and degree of carboxylation. Besides, to validate the esterification reaction and existence of carboxylic groups in the adsorbent, CESNPs were characterized metrologically via analytical tools for carboxyl content estimation and instrumental tools using Fourier-transform infrared spectroscopy (FTIR) spectra and scanning electron microscopy (SEM) morphological analysis.
Findings
The overall adsorption potential of CESNPs was found to be 136 mg/g when a 0.1 g adsorbent dose having 190.8 meq/100 g sample carboxyl content at pH 5 for 60 min contact time was used. Besides, increasing the degree of carboxylation of the CESNPs expressed as carboxyl content would lead to the higher adsorption capacity of cadmium ions. FTIR spectroscopy analysis elucidates the esterification reaction with the appearance of a new intense peak C=O ester at 1,700 cm−1, whereas SEM observations reveal some atomic/molecules disorder after esterification.
Originality/value
The innovation addressed here is undertaken by studying the consequence of altering the extent of carboxylation reaction expressed as carboxyl contents on the prepared CESNPs via a simple dry technique with a small amount of water, energy and toxic chemicals that were used as a sustainable bio nano polymer for cadmium ions and basic dye removal from wastewater effluent in comparison with other counterparts published in the literature.
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Zircoaluminate metallo organics constitute a unique family of surface modification agents which are cost effective in irreversibly modifying all inorganic fillers/pigments, carbon…
Abstract
Zircoaluminate metallo organics constitute a unique family of surface modification agents which are cost effective in irreversibly modifying all inorganic fillers/pigments, carbon black, and many organic pigments. Direct in situ addition to coating resin or solvent (at 0.5–1.5 phf) will result in pronounced viscosity reduction (50.95%), reduced settling and particulate agglomeration, and improved colour strength and opacity. Zircoaluminates also improve salt spray resistance, enhance adhesion to metal substrates and eliminate telegraphing.
Zahra Shams Ghahfarokhi, Mojtaba Bagherzadeh, Ebrahim Ghiamati Yazdi and Abbas Teimouri
The purpose of this paper is study of the type of functional group and its situation on phenyl molecule, in increasing the corrosion protection of modified graphene layers by it…
Abstract
Purpose
The purpose of this paper is study of the type of functional group and its situation on phenyl molecule, in increasing the corrosion protection of modified graphene layers by it. Corrosion protection efficiency of graphene was raised via modifying the surface of graphene-coated carbon steel (CS/G) by using aromatic molecules. Phenyl groups with three different substitutions including COOH, NO2 and CH3 grafted to graphene via diazonium salt formation route, by using carboxy phenyl, nitro phenyl and methyl phenyl diazonium salts in ortho, meta and para spatial situations.
Design/methodology/approach
Molecular bindings were characterized by using X-ray diffractometer, fourier-transform infrared spectroscopy (FTIR), Raman and scanning electron microscopy (SEM)/ energy dispersive X-ray analysis (EDXA) methods. Anti-corrosion performance of modified CS/G electrodes was evaluated by weight loss and electrochemical techniques, potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy, in 3.5 per cent NaCl solution.
Findings
The obtained results confirmed covalently bonding of phenyl groups to the graphene surface. Also, the observed results showed that substitution spatial situations on phenyl groups can affect charge transfer resistance (Rct), corrosion potential (Ecorr), corrosion current density (jcorr) and the slope of the anodic and cathodic reaction (ßa,c), demonstrating that the proposed modification method can hinder the corrosion reactions. The proposed modification led to restoring the graphene surface defects and consequently increasing its corrosion protection efficiency.
Originality/value
The obtained results from electrochemical methods proved that protection efficiency was observed in order COOH < NO2 < CH3 and MPD in the para spatial situation and showed the maximum protection efficiency of 98.6 per cent in comparison to other substitutions. Finally, the ability of proposed graphene surface modification route was further proofed by using surface methods, i.e. SEM and EDXA, and contact angles measurements.
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Darya Ewaznezhad Fard, Saeideh Gorji Kandi and Marziyeh Khatibzadeh
The purpose of this study is to investigate the changes in the performance of ink formulations caused by the addition of compounds that improve the ink’s physical properties to…
Abstract
Purpose
The purpose of this study is to investigate the changes in the performance of ink formulations caused by the addition of compounds that improve the ink’s physical properties to achieve an optimum formulation for inkjet printing, because of the importance and simplicity of this method.
Design/methodology/approach
Ink samples were formulated using Acid Red 14 as ink colorant, different percentages of polymeric compounds including polyvinyl alcohol (PVA), polyvinylpyrrolidone and Carboxy methyl cellulose (CMC) as viscosity modifier compounds and surfactant as the surface tension enhancer. Formulated samples were adjusted in terms of fluid physical properties e.g. viscosity, density and surface tension, and the effect of used compounds on the improvement of both physical and colorimetric properties such as viscosity, surface tension, colorimetric coordinates and lightfastness has been evaluated to achieve the optimum printing inks to be printed on three different substrates.
Findings
The experimental observations showed that CMC was the most compatible compound as the viscosity modifier as its viscosity value was in the printable range of 2–22 cP. Moreover, a flow-curve test was applied to the ink samples and their Newtonian behavior was approved. Based on the spectrophotometric test results of printed samples, the samples containing PVA provided acceptable lightfastness in comparison to other ink samples on every used substrate.
Originality/value
An optimum relation between colorimetric coordinates of the printed samples and ink formulation could be considered and achieved.
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Galal H. Elgemeie and Doaa M. Masoud
This paper aims to focus on the most popular technique nowadays, the use of microwave irradiation in organic synthesis; in a few years, most chemists will use microwave energy to…
Abstract
Purpose
This paper aims to focus on the most popular technique nowadays, the use of microwave irradiation in organic synthesis; in a few years, most chemists will use microwave energy to heat chemical reactions on a laboratory scale. Also, many scientists use microwave technology in the industry. They have turned to microwave synthesis as a frontline methodology for their projects. Microwave and microwave-assisted organic synthesis (MAOS) has emerged as a new “lead” in organic synthesis.
Design/methodology/approach
Using microwave radiation for synthesis and design of fluorescent dyes is of great interest, as it decreases the time required for synthesis and the synthesized dyes can be applied to industrial scale.
Findings
The technique offers many advantages, as it is simple, clean, fast, efficient and economical for the synthesis of a large number of organic compounds. These advantages encourage many chemists to switch from the traditional heating method to microwave-assisted chemistry.
Practical implications
This review highlights applications of microwave chemistry in organic synthesis for fluorescent dyes. Fluorescents are a fairly new and very heavily used class of organics. These materials have many applications, as a penetrant liquid for crack detection, synthetic resins, plastics, printing inks, non-destructive testing and sports ball dyeing.
Originality/value
The aim value of this review is to define the scope and limitation of microwave synthesis procedures for the synthesis of novel fluorescent dyes via a simple and economic way.
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Ansar Ali Sk, Pardeep Kumar and Sandeep Kumar
The purpose of the study is to developed the effect of Nusselt number on impeller diameter in agitated vessel, which is beneficial to find out the heat transfer coefficient in the…
Abstract
Purpose
The purpose of the study is to developed the effect of Nusselt number on impeller diameter in agitated vessel, which is beneficial to find out the heat transfer coefficient in the process industry. A comparison has been done between the experimental and calculated Nusselt numbers with standard deviation found to be 8.03 per cent.
Design/methodology/approach
For studying the effect of impeller diameter on Nusselt Number, the heat transfer measurements were made with three different impellers of diameter. Although the diameter of impeller, Da shows its effect in Reynolds number, an attempt has been made to find the relationship between the impeller diameter and Nusselt number. A correlation between (NNuj/N″Pra1/3 N″Rea2/3) vs Da/DT and (NNuoc/N″Pra1/3 N″Rea2/3) vs Da/Dc in which data of three fluids [1, 2 and 4 per cent carboxy methyl cellulose solution of A type (CMC-A) solutions] have been plotted.
Findings
The heat transfer data for agitated Newtonian and non-Newtonian fluids have been successfully correlated by using the viscosity of the fluid evaluated at the impeller tip assuming a cylinder of diameter equal to that of impeller rotating in an infinite fluid. Data of 1, 2 and 4 per cent CMC-A, for three impeller diameters, have been correlated by equations. Using the above concepts of Reynolds and Prandtl numbers, Nusselt Numbers and Da/DT, it is also possible to correlate the available published data for other non-Newtonian fluids obtained with different impeller geometries.
Originality/value
A set up was made for studying the effect of impeller diameter, the heat transfer measurements were made with three impellers of diameter 7.5, 12.7 and 18.35 cm respectively. Although the diameter of impeller, Da shows its effect is Reynolds number, an attempt has been made to find the effect of Da/DT ratio on Nusselt number.
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Many information scientists are concerned with the operation of document retrieval systems serving scientists in various fields. The scientists served by these systems are often…
Abstract
Many information scientists are concerned with the operation of document retrieval systems serving scientists in various fields. The scientists served by these systems are often members of what have been called invisible colleges, groups of scientists in frequent communication with one another and involved with highly specialized subject matters. Often such groups are considered to share an intellectual perspective regarding this subject matter, which is sometimes referred to as a paradigm.
Govind Umarji, Supriya Ketkar, Ranjit Hawaldar, Suresh Gosavi, Kashinath Patil, Uttam Mulik and Dinesh Amalnerkar
The purpose of this paper is to ascertain chemical changes occurring at various stages involved in processing of silver‐based photoimageable thick films; and to determine ensuing…
Abstract
Purpose
The purpose of this paper is to ascertain chemical changes occurring at various stages involved in processing of silver‐based photoimageable thick films; and to determine ensuing topographical features which other wise appeared to be hindered in 2D scanning electron microscopy.
Design/methodology/approach
Surface sensitive techniques, viz. X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used.
Findings
Interfacial adhesion of silver film with substrate (Al2O3) was specifically looked into with respect to role played by photoimaging (before and after exposure to ultra‐violet light). XPS results revealed occurrence of subtle chemical changes in terms of unsaturation to saturation in C−C bonding and also an interesting C−Al bonding which presumably improves mechanical adhesion of unfired film with the alumina substrate. AFM was carried out to examine the surface roughness, particle size, and microstructure of film which are very important from the standpoint of high‐frequency applications.
Originality/value
Surface sensitive techniques like XPS and AFM were exclusively used in order to characterize silver‐based photoimageable thick films.
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