The interactions of copper substrate with titanium-alloyed Sn-Zn eutectic solders have been studied. Two series of experiments have been performed. The first one consisted in differential thermal analyses of Sn-Zn nearly eutectic alloys containing from 1.3 to 2.2 wt. % Ti. Diffusion couples consisted of Cu-wires and Sn-Zn-Ti liquid solders, produced at 250 and 275 OC have been prepared in the s...

Deformation pattern of the northeastern part of the Iranian-Arabian collision zone (i.e., mainly Sanandaj-Sirjan Belt or Zone) is the main concern of this paper. Here, we investigate the stress distribution and displacement pattern of Eghlid-Deh Bid area as affected by the position of Zagros suture using a three dimensional mechanical model. The modeled area is located between the Zagros Thrust...

We study a singular perturbation problem for a certain type of reaction diiusion equation with a space-dependent reaction term. We compare the eeect that the presence of boundary layers versus internal layers has on the existence and stability of stationary solutions. In particular, we show that the associated eigenvalues are of diierent orders of magnitude for the two kinds of layers.

In matrix acidizing operations, the main goal is increasing permeability. For production engineers, it is desirable that acid could be injected into whole [M.N.1] [amehri.gh2] pay zone. Sometimes, this pay zone has a long height and various sub-layers which have different permeability values. To prevent acid from going completely into the most permeable sub-layer, one of the useful techniques i...

Friction stir processing (FSP) was used for the fabrication of Al-B4C surface composite. Al-Mg-Si alloy was considered as the substrate and B4C particles were incorporated into the substrate by thermo-mechanical effect of FSP. The effect of tool dimensions and different rotational speeds on the microstructure and microhardness of the composite layers was evaluated and the optimum process parame...

Articular and growth plate cartilage are discrete tissues but arise from a common cartilaginous condensation and have comparable spatial architectures consisting of distinct layers of chondrocytes. To investigate similarities and differences between articular and growth plate cartilage and to explore transcriptional changes that occur during the onset of their divergence, we performed manual mi...

The effects of digitalis (ouabain infusion, priming dose of 10 Ag/kg/min followed by 2.0 gg/kg/min) on subepicardial and subendocardial ischemic dysfunction during partial occlusion (59.4% reduction in coronary flow) and total coronary occlusion were evaluated in 14 dogs using pairs of ultrasonic crystals implanted in the epicardial and endocardial layers. After 30 minutes of partial coronary o...

Qara Aqaj titanium potential is one of the two major known titanium resources in Iran. The main host rocks of the ore body are ultramafics including wehrlite and lherzolite with minor clinopyroxenite. Qara Aqaj intrusion is composed mainly of ultramafic-mafic rocks, layered gabbro, diorite, microdiorite and some monzonite and alkali syenite. This intrusion has intruded the basement complex (amp...

The effects of digitalis (ouabain infusion, priming dose of 10 micrograms/kg/min followed by 2.0 micrograms/kg/min) on subepicardial and subendocardial ischemic dysfunction during partial occlusion (59.4% reduction in coronary flow) and total coronary occlusion were evaluated in 14 dogs using pairs of ultrasonic crystals implanted in the epicardial and endocardial layers. After 30 minutes of pa...