We studied intra-annual wood density profiles of Douglas-fir tree rings (Pseudotsuga menziesii [Mirb.] Franco) in southwestern Germany. Growth rate varies differently over time throughout the circumference of trees. This leads to differences in wood formation, which can be observed in the shape of the density profiles of the same tree ring measured in different radial directions. Due to this sp...

Steel foam offers potential advantages over aluminum foams and other metallic foams. The inherent strength of steel combined with the reduced density of foam presents an attractive material with greater strength and modulus than light alloy foams, greatly reduced density relative to solid steel, and efficient energy absorption. However, thus far there have been few reports describing efforts to...

Acoustic scattering techniques provide a unique and powerful tool to remotely investigate the physical properties of the ocean interior over large spatial and temporal scales. With high-frequency acoustic scattering it is possible to probe physical processes that occur at the microstructure scale, spanning submillimeter to centimeter scale processes. An acoustic scattering model for turbulent o...

In the present work, Al2O3-CeO2 composite nanopowders were synthesized via co-precipitation method. The sinterability of the synthesized powders was investigated. The results showed that the transformation of transition phases of alumina to α-Al2O3 takes place at 1200 °C. TEM images showed that the powders was composed of nanoparticles in the range of 30−70 nm. The densification of composites s...

Laboratory measurements of high-frequency broadband acoustic backscattering (200-600 kHz) from the diffusive regime of double-diffusive microstructure have been performed. This type of microstructure, which was characterized using direct microstructure and optical shadowgraph techniques, is identified by sharp density and sound speed interfaces separating well-mixed layers. Vertical acoustic ba...

Abstract: In this paper‚ the physical and mechanical properties of Al nanocomposite reinforced with CNTs wereinvestigated. High purity Al powder and Carbon Nanotubes (CNTs) with different percentage were mixed by ballmilling method and the composite was fabricated by cold pressing followed by sintering technique. The variation ofdensity and hardness of composite with CNTcontent was investigated...

• Fracture behavior in porous materials of different relative densities are investigated. Crack paths low-density solids heavily influenced by the microstructure, whereas, high-density controlled global remote load. Transition cracking is at around 50% density. Porous widely used engineering applications because their high stiffness, strength, and low Those advantages mainly due to open microst...

This paper reports on the precipitation behaviour and microstructural evolution in ~20% cold rolled NbMoV and V single microalloyed low carbon steels during intercritical annealing. The microstructure and precipitation behaviour were studied by optical and scanning/transmission electron microscopy and microanalysis, X-ray diffraction technique and Vickers hardness testing. After intercritical a...

this study was carried out to evaluate empirical models of competition, as two separated experiments based on a randomized complete block design with 3 replications at agricultural faculty of bu-ali sina university, in 2008-2009. in both experiments, alvand and sayson cultivar were planted with densities of 450 plants m-2. in the 1st experiment, feral rye (secale cereale) with densities of 0, 2...