Microbial growth within the water-saturated subsurface environment was investigated by exposing sandy sediments to groundwater for 12 weeks at a depth of 10 or 20 m in a stainless-steel groundwater well. Washing and heating the sediment to 600 degrees C (removal of organic carbon) prior to the exposure did not prevent the natural microbial community from colonizing the sterilized sediment sampl...

This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) beams internally reinforced with steel bars and externally bonded with carbon fiber-reinforced polymer (CFRP) sheets fixed by adhesive and hybrid jointing techniques. In particular, attention is paid to the load resistance and failure modes of composite beams. The steel fibers were used to avoiding the rip...

A process was developed for fabricating arrays of micro-channels in shape-memory NiTi for bone implant applications, with a tailorable internal architecture expected to improve biomechanical compatibility and osseointegration. Ni-51.4 at.% Ti with 24-34 vol.% porosity was fabricated by electrochemical dissolution of parallel layers of steel wire meshes embedded within a NiTi matrix during hot p...

A major objective of Army technology is the development of lighter and stronger platforms such as armored vehicles for Future Combat systems and Future Force. Here we show that carbon nanotubes could be the basis of such a possibility. It is shown for the first time that a carbon nanotube-iron composite, iron being the principle component of steel, has significantly enhanced mechanical strength...

The paper demonstrates the correlation between the chemical composition of steel grades and the hardness as well as the formability of laser welds generated with modern automotive high strength steel grades. At the very low heat input of industrial laser welding and the resulting extremely high cooling rate, the weld hardness is fully controlled by the carbon content of the base materials and n...

In the present study, the microstructure and mechanical properties of the dissimilar welding between ASTM A335 low alloy steel and ER309L austenitic stainless steel were investigated using the gas tungsten arc welding process. The welding of dissimilar materials between ASTM A335 low alloy steel and ER309L austenitic stainless steel was found to have a significant effect on the microstructure w...

■ Carbon storage in forests. In one study, taking “no action” rather than harvesting stored more carbon. ■ Carbon storage considering forests, wood products, and concrete substitution. Collectively a 45-year harvest cycle, wood products and substitution for non-wood products stored more carbon than the “no action” managed forest scenario. ■ Carbon storage in houses. Wood-framed houses store mor...

AIM The aim of this study was to evaluate the carious dentin removal efficacy of new rotary polyamide burs capable of selectively removing infected dentin without removing sound dentin. METHODS AND MATERIALS This study included 40 subjects with bilateral occlusal carious lesions on mandibular first permanent molars. The lesions were randomly assigned to receive one restoration after carious d...

In the present paper, changes in mechanical properties of Portland cement-based mortars due to the addition of carbon nanotubes (CNT) and corrosion of embedded steel rebars in CNT cement pastes are reported. Bending strength, compression strength, porosity and density of mortars were determined and related to the CNT dosages. CNT cement paste specimens were exposed to carbonation and chloride a...