A variety of materials require functionally graded cellular microstructures whose porosity is engineered to meet specific applications (e.g. mimic bone structure for orthopaedic applications; fulfil mechanical, thermal or acoustic constraints in structural foamed components, etc.). Although a huge variety of foams can be manufactured with homogenous porosity, there are no generic processes for ...

We investigated four acrylic cement preparation techniques for their effects on cement porosity: hand mixing, pressurization in a pneumatic pistol, centrifugation, and vacuum mixing. All the techniques were tested on three types of cement with different viscosity characteristics. The best results were obtained with vacuum mixing using a newly designed experimental system, yielding porosity redu...

Effective mass-transfer kinetics depend on particle-size distribution (PSD) and particle porosity (among other complex phenomena). The porediffusion flux can vary with adsorbate loading – if the amount of adsorbed species is sufficiently large it can lead to hindrance effects that substantially change particle porosity. By use of batch kinetic adsorption experiments the general rate model was u...

Therefore, the new method, called the grey level method, which reflects the phenomenon of image processing and computation of ration between the volume of voids and the total volume of the entire sample, was considered and improved in term of image noise and artifacts. The volumes of 2D CT image as a surface are achieved by means of integrating the surface with operations relating to image hist...

Porosity is a result of a deficiency in the production process that could lead into the mechanical degradation of CFRP composite structures. Therefore, some checkpoints for determining its presence during part manufacturing have to be established, verifying that precise threshold values are not exceeded. Currently, porosity characterization is carried out by an indirect way using ultrasonic tec...

From the known statistics of fiber-fiber contacts in random fiber networks, an analytic estimate is obtained for the variance of local porosity in random fiber suspensions and evolving filtrate networks. The variance of local porosity, and hence the distribution of projected areal density, seem to depend on fiber geometry only through the cube of mean diameter. Also, the coefficient of variatio...

From the known statistics of fibre-fibre contacts in random fibre networks, an analytic estimate is obtained for the variance of local porosity in random fibre suspensions and evolving filtrate networks. The variance of local porosity, and hence the distribution of projected areal density, seems to depend on fibre geometry only through the cube of mean diameter. Also, the coefficient of variati...

The role of vacuum mixing on the reduction of porosity and on the clinical performance of cemented total hip replacements remains uncertain. We have used paired femoral constructs prepared with either hand-mixed or vacuum-mixed cement in a cadaver model which simulated intra-operative conditions during cementing of the femoral component. After the cement had cured, the distribution of its poros...

Characterization of porosity in carbonate rocks is important in the oil and gas industry since a major hydrocarbons field is formed by this lithology and they have a complex media porous. In this context, this research presents a study of the pore space in limestones rocks by x-ray microtomography. Total porosity, type of porosity and pore size distribution were evaluated from 3D high resolutio...

in this study, the microstructure and properties of foam glass obtained as a result of the interaction of the waste glass with sic as the foaming agent and fe2o3 as the oxidizing agent have been investigated using scanning electron microscopy (sem), as well as three-point bending and pycnometery tests. first, the temperature and optimized amount of sic for making foam glass was determined. the ...