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This paper aimed to analyze removed particles from stationary specimen-aluminum (Al-99.92) produced by vibratory cavitation erosion tests in distilled water and glycerol-water mixtures.

The particle morphology which include particle surface topography, size distribution, particle size parameters and particle shape parameters were examined for distilled water and glycerol-water mixtures having different viscosities.

The results showed that the variation of size parameters with viscosity was very similar to the variation of weight loss with viscosity. Both the size parameters and weight losses show a monotonic decrease in going from distilled water to glycerol-water mixtures having viscosity about 10.1 cSt, beyond which the change is very small. On the other hand, the shape parameters were much less sensitive to distinguish between the particles produced in water and glycerol-water mixtures. The mechanism of cavitation erosion is investigated in detail through observations of the removed particles. The particle surfaces topography demonstrated that the mechanism in water and glycerol-water mixtures was fatigue failure.

Cavitation often occurs in almost all machines that handle liquids, especially at high speeds, leading to irreparable damage of the components of these machines. Elucidation of such complex phenomenon demands full characterization of the erosion mechanism and controlling parameters inherent to it, so that cavitation erosion can be prevented or at least be reduced through adequate information and collection of relevant data under different operating conditions. Very few studies have been made to approach the viscosity effect upon cavitation erosion from the particle analysis standpoint. The aim of the present work is to identify the effect of liquid viscosity on the size, shape characteristics of the erosion particles and their morphological features. The prevailed mechanisms of wear and particle generation have been proposed based on the acquired information from particle analysis.

The rate of copper dissolution in the presence of phosphoric acid‐alcohol mixtures was studied by measuring the limiting current density which represents that the rate of electropolishing is decreased by increasing phosphoric acid concentration, electrode height, and mole fraction of alcohol. Thermodynamic parameters are calculated. The rotating disk electrode is being used as a tool to study the influence of organic solvent addition on the rate of electropolishing of copper. Different reaction conditions such as temperature, speed of rotation of copper disk, the physical properties of solution are studied to obtain a dimensionless correlation between all these parameters. The data can be correlated by the following equations: Sh = 1.835 (Sc)^0.33 (Re)^0.36 (for ethylene glycol) Sh = 1.25 (Sc)^0.33 (Re)^0.5 (for glycerol) It is obvious that the exponent in the two cases denotes a laminar flow mechanism.

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.

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, D_a 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 (N_Nuj/N^″_Pra^1/3 N^″_Rea^2/3) vs D_a/D_T and (N_Nuoc/N^″_Pra^1/3 N^″_Rea^2/3) vs D_a/D_c 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.

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 D_a/D_T, it is also possible to correlate the available published data for other non-Newtonian fluids obtained with different impeller geometries.

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 D_a/D_T ratio on Nusselt number.

This paper aims to focus on research work related to metamaterial-based sensors for material characterization that have been developed for past ten years. A decade of research on metamaterial for sensing application has led to the advancement of compact and improved sensors.

In this study, relevant research papers on metamaterial sensors for material characterization published in reputed journals during the period 2007-2018 were reviewed, particularly focusing on shape, size and nature of materials characterized. Each sensor with its design and performance parameters have been summarized and discussed here.

As metamaterial structures are excited by electromagnetic wave interaction, sensing application throughout electromagnetic spectrum is possible. Recent advancement in fabrication techniques and improvement in metamaterial structures have led to the development of compact, label free and reversible sensors with high sensitivity.

The paper provides useful information on the development of metamaterial sensors for material characterization.

Monodisperse microfluidic emulsions – droplets in another immiscible liquid – are beneficial to various technological applications in analytical chemistry, material and chemical engineering, biology and medicine. Upscaling the mass production of micron-sized monodisperse emulsions, however, has been a challenge because of the complexity and technical difficulty of fabricating or upscaling three-dimensional (3 D) microfluidic structures on a chip. Therefore, the authors develop a fluid dynamical design that uses a standard and straightforward 3 D printer for the mass production of monodisperse droplets.

The authors combine additive manufacturing, fluid dynamical design and suitable surface treatment to create an easy-to-fabricate device for the upscaling production of monodisperse emulsions. Considering hydrodynamic networks and associated flow resistance, the authors adapt microfluidic flow-focusing junctions to produce (water-in-oil) emulsions in parallel in one integrated fluidic device, under suitable flow rates and channel sizes.

The device consists of 32 droplet-makers in parallel and is capable of mass-producing 14 L/day of monodisperse emulsions. This convenient method can produce 50,000 millimetric droplets per hour. Finally, the authors extend the current 3 D printed fluidics with the generated emulsions to synthesize magnetic microspheres.

Combining additive manufacturing and hydrodynamical concepts and designs, the authors experimentally demonstrate a facile method of upscaling the production of useful monodisperse emulsions. The design and approach will be beneficial for mass productions of smart and functional microfluidic materials useful in a myriad of applications.

The paper describes a fast forward electromagnetic model built with help of commercial software. The purpose of this paper is to create an efficient and robust electromagnetic field model that could be easily plugged into a working microwave imaging system. The secondary purpose is to evaluate advantages and disadvantages of such a commercial packages for creating such a model.

In this paper the authors decided to build the model using COMSOL Multiphysics software suite, ultimately comparing its result to measurements of a real device. The numerical model was created in an iterative fashion in order to determine how much details are needed to make it reliable, while keeping it efficient.

The authors found that the commercial software seems like a viable platform for developing electromagnetic solvers. The resulting computer model is easy to prepare, run and integrate with external tools.

Using the experience in building numerical models of various systems the authors came to the conclusion that developing some in-house code is a very non-efficient technique as it slows down the progress of the research team once the team changes. Transfer of knowledge associated with the numerical tools is much easier when the tools are constructed using a common platform, i.e. commercial packages. It does not really matter if the software is free or proprietary as long as the platform provides efficient tools assisting in model preparation and data visualization.

One of the main advantages of using such a full field electromagnetic model is the ability to investigate an impact of different properties of the system (length of antennas, liquid parameters) on its performance. Thanks to the use of commercial software it is much easier to pass the project to new people too.

The presented numerical model utilizes a frugal meshing scheme which allows faster execution while keeping required accuracy of solutions. Using this model the authors were able to diagnose important geometrical details that could affect the performance of the system.

Free convective flow in a square enclosure with one of the vertical walls heated and with the opposite vertical wall cooled to a uniform temperature, the remaining walls being adiabatic, has been numerically studied. The heat flux at the heated wall is spatially uniform but is, in general, varying in a stepwise manner with time. The flow has been assumed to be laminar and two‐dimensional. Fluid properties have been assumed constant except for the density change with temperature that gives rise to the buoyancy forces. The governing equations, expressed in terms of stream function and vorticity, have been written in dimensionless form. The resultant equations have been solved using the finite‐element method. Because of the possible applications that motivated the study, results have only been obtained for a Prandtl number of 0.7. Results have then been obtained for modified Rayleigh numbers between 1,000 and 1,000,000 for a wide range of dimensionless amplitudes and periods of the heat flux variation.

To conduct a numerical study on two‐dimensional, transient, buoyant flow inside an air‐filled 45°‐inclined enclosure, heated and cooled on adjacent walls.

The governing equations obtained through the stream function‐vorticity formulation are solved using finite differences. Flow characteristics have been investigated for an aspect ratio of 1. Calculations are carried out for the Rayleigh numbers in the range of 10³≤Ra≤5×10⁷.

With the increasing Rayleigh number, four distinct flow regimes were identified based on the time variations of the mid‐point stream function and the mean Nusselt number at the heated wall as well as those of flow and temperature fields: steady flow with symmetric two cells at low Ra; steady flow with asymmetric two cells at lower moderate Ra; oscillatory flow with the periodic nature at upper moderate Ra; and oscillatory flow in chaotic nature at higher Ra range.

The distinct flow regimes are observed only at ϕ=45°; a small deviation of the tilting angle from ϕ=45° results in the disappearance of the distinction.

The purpose of this paper is to evaluate the effect of different amounts of sodium hydroxide (NaOH) introduced during the resin synthesis on the properties of bark‐phenol‐formaldehyde (BPF) adhesives aims at achieving a balance between storage life and other properties of BPF adhesives.

Based on the best synthetic technologies for the production of BPF adhesives obtained in a previous study, a new synthetic technology is developed for the production of BPF adhesives that involve a three‐step addition of NaOH using different amounts of NaOH in the third charge. Gel permeation chromatography is used to evaluate properties of the phenol‐formaldehyde (PF) and BPF adhesives.

The amount of NaOH in the third charge has an important influence on many BPF adhesive properties. The paper determines that the synthetic technology involving three‐step NaOH additions with only water introduced in the third charge of NaOH produces a BPF adhesive with the longest storage life and best bonding strength.

BPF adhesives are very complex systems with many unknown variables.

The improved storage life of the BPF adhesive prepared with the new synthetic technology is comparable to that of a commercial PF adhesive, which indicates that this new technology shows greater potential for commercial applications.

A new synthetic technology is developed to produce a BPF adhesive that is more comparable to commercial PF adhesives than other BPF adhesives in terms of storage life and other resin properties.

The aim of this paper is to solve the toxic and harmful problems caused by traditional volatile corrosion inhibitor (VCI) and to analyze the effect of the layered structure on the enhancement of the volatile corrosion inhibition prevention performance of amino acids.

The carbon dots-montmorillonite (DMT) hybrid material is prepared via hydrothermal process. The effect of the DMT-modified alanine as VCI for mild steel is investigated by volatile inhibition sieve test, volatile corrosion inhibition ability test, electrochemical measurement and surface analysis technology. It demonstrates that the DMT hybrid materials can improve the ability of alanine to protect mild steel against atmospheric corrosion effectively. The presence of carbon dots enlarges the interlamellar spacing of montmorillonite and allows better dispersion of alanine. The DMT-modified alanine has higher volatilization ability and an excellent corrosion inhibition of 85.3% for mild steel.

The DMT hybrid material provides a good template for the distribution of VCI, which can effectively improve the vapor-phase antirust property of VCI.

The increased volatilization rate also means increased VCI consumption and higher costs.

Provides a new way of thinking to replace the traditional toxic and harmful VCI.

For the first time, amino acids are combined with nano laminar structures, which are used to solve the problem of difficult volatilization of amino acids.