Freeze-drying is one of the most used methods for preparing scaffolds and is very sensitive to the material and operational parameters such as nucleation temperature, thermal properties of the mold, cooling rate, set freezing point, and slurry height. In the present study, a Finite Element Method (FEM) based code was developed to investigate the effects of such parameters and to eventually ...

Filter is one of the main components of embankment dams. By a simple but effective performance, filter protects the dam against erosion and soil scouring in impervious core caused by leakage (piping) and makes it safe. Interaction between filter and erodible base soil is a complex phenomenon which is dependent upon several factors, and has challenged researchers for better understanding the fil...

mixed clayey soils occur as mixtures of sand (or gravel) and clay in widely varying proportions. their engineering behavior has not been comprehensively studied yet. an experimental program, comprising monotonic, cyclic, and post-cyclic triaxial tests was undertaken on compacted clay-granular material mixtures, having different proportions of clay and sand or gravel. this paper presents the res...

In the present contribution a number of porous materials has been investigated with various porosities (75 % < ψ < 93 %), mean pore diameters (360 < δ50 < 50,000 nm), and pore size distributions which are partly narrow and partly wide spread. The effective thermal conductivities have been measured between 500 and 1000 K in nitrogen, helium, argon and a nitrogen/hydrogen mixture (60/40 mol-%). R...

A theoretical analysis is carried out to investigate the pore-fluid pressure gradient and effective vertical-stress gradient distribution in fluid-saturated porous rock masses in layered hydrodynamic systems. Three important concepts, namely the critical porosity of a porous medium, the intrinsic pore-fluid pressure and the intrinsic effective vertical stress of the solid matrix, are presented ...

Electrochemical and high-speed imaging techniques are used to study the abilities of ultrasonically-activated bubbles to clean out micropores. Cylindrical pores with dimensions (diameter × depth) of 500 μm × 400 μm (aspect ratio 0.8), 125 μm × 350 μm (aspect ratio 2.8) and 50 μm × 200 μm (aspect ratio 4.0) are fabricated in glass substrates. Each pore is contaminated by filling it with an elect...

the main role ofcore in earth dams is to reduce and control the seepage flow through the dam. in order to achieve this purpose, the core material is usually selected from pure or mixed clays.due to very small coefficient of permeability, the clay cores can prevent water leakageeasily. however, pore water pressures developed inside the core during construction, can not be dissipated quickly. as ...

Periodic pressure measurements made during the depletion of oil fields and virgin pressure measurements through normallyand over-pressured sequences in sedimentary basins both demonstrate that changes in pore pressure and minimum horizontal stress (σh) are coupled to one another. Pore pressure/stress coupling is predicted by poroelastic theory. Data from the North Sea (Ekofisk Field) and Texas ...

pore pressure could be estimated prior to drilling using seismic velocities. applying this approach, the final calculated pore pressure is highly affected by accuracy of the obtained velocity data. in order to generate an accurate velocity cube with proper resolution, velocities from well logs and post-stack 3-d seismic inversion are used along with stacking velocities from velocity analysis of...