In this work, a tracer study on pore initiation in anodic alumina in oxalic acid was performed. Effects of some experimental parameters such as applied electrical potential, electrolyte composition and heat pretreatment were evaluated. Electrochemical and morphological experiments were performed using potentiostatic anodizing and scanning electron microscopy (SEM) techniques, respectively. Effe...

A laboratory is described for the preparation and analysis of high-purity clinical chemicals. The work area is designed to minimize contact of high-purity materials with the main source of contamination, the chemical operator. We discuss the use of a perforated, curved, anodized aluminum membrane that permits completely free access to the work area and describe the general construction of the l...

The acoustic attenuation performance of perforated dissipative circular expansion chambers with inlet/outlet extensions is investigated. The eigenvalues and eigenfunctions of the sound field are analytically determined in the extended inlet/outlet circular ducts, upstream/downstream end annular dissipative chambers, and the central perforated dissipative expansion chamber. Utilizing the continu...

Experiments were conducted to compare the annealing of nano-porous aluminum oxide membranes by 2.45 GHz microwave radiation and by conventional (resistive element) furnace heating. The starting material was Al2O3 membranes that were 60 microm thick, 13 mm in diameter, and containing pores of approximately 200 nm diameter. Changes in the porosity and morphology were recorded from digital process...

A broadband metamaterial absorber (MA) composed of hexagonal-arranged single-sized titanium nitride (TiN) nano-disk array and monolayer molybdenum disulfide (MoS2) is studied using finite-difference time-domain (FDTD) simulations. The structure of TiN nano-disk array/dielectric silica (SiO2)/aluminum (Al) is adopted in our design. By optimizing the dimension parameters of the structure, an aver...

For high end heat exchanging applications in cryogenics and space application, compactness and effectiveness are the key factors which determine the performance of heat exchanger. Matrix heat exchanger with perforated plate heat surfaces has both criterions to suit into these applications. High thermal conductivity plate and low thermal conductivity spacers are stacked together to obtain low lo...

A two-dimensional analytical solution is developed to determine the acoustic performance of a perforated single-pass, concentric cylindrical silencer filled with fibrous material. To account for the wave propagation through absorbing fiber and perforations, the complex characteristic impedance, wave number, and perforation impedance are employed. With expressions for the eigenvalues and eigenfu...

In this work, a finite element approach is presented for modelling sound propagation in perforated dissipative mufflers with non-homogeneous properties. The spatial variations of the acoustic properties can arise, for example, from uneven filling processes during manufacture and degradation associated with the flow of soot particles within the absorbent material. First, the finite element metho...