علیرضا شافعی

In this paper, nano-composite powder of TiO2 and multi-walled carbon nanotubes (CNTs) was synthesized by in-situ sol-gel method. The effect of processing parameters of benzyl alcohol, H2O and CNT content (1 and 10 wt.%) on the prepared powder morphology was investigated. The samples were characterized via field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. Firstly, the influence of calcination stage on the powders structure was evaluated. XRD results showed amorphous structures for the composite powders before calcination and the dominant structure of anatase TiO2 after calcination treatment. FESEM results showed a non-uniform and agglomerated morphology without benzyl alcohol. Furthermore, addition of Tetrabutyl-orthotitanate solution to the initial solution containing H2O as the hydrolysis agent resulted in finer powder microstructure with uniform coating of TiO2 on CNTs due to slower hydrolysis reaction. The effect of CNTs on the morphology depends on percent of CNTs. Also, composite powder with higher particle size was formed with the decrease of CNT content from 10 to 1 percent which is attributed to the decreased and less accessible surface area to TiO2 particles formation.

The present research is aimed at investigation of geometry and kinematics of joints, relationships and temporal and spatial distribution of the joints regarding the two deformational events within the Purkan-Vardij thrust sheet. We also studied the relationships between development of different joint sets and the lithological characteristics of layers of the Karaj Formation. Considering outcrops of volcaniclastic and igneous rocks of variable lithology, we have divided them into five different rock units including thick-bedded to massive tuffs, thin- to mediumbedded tuffs, tuff-shale-sandstone sequence, shale, and igneous units. Joint study was carried out using selection method, and in part using listing method, which are useful for quick survey and statistical purposes. Joint classification was carried out using concentrations of pole to joint planes. We have used the fracture spacing index (FSI), which is an important parameter in controlling morphology and erodibility of the rock units; it is also useful for prediction of joint spacing in other layers and in surrounding areas. These characteristics are useful in road construction, tunneling and other engineering projects. A comparison of the FSI in different rock units indicates that the intrusive bodies and thick-bedded units develop a highly variable FSI with a wide range of spacings, which in most cases due to lower concentration of the joints show lower erodibility as compared to the other rock units, and therefore have more relief in their outcrops. Two major joint sets, J1 and J2, show the highest frequency within the classified joint sets. Both of these sets are of extension joint type, and their strikes indicate the s1 direction during their development. Our study in this research confirms that amount of the strain produced by the joints is very small.

The North Tehran Fault with a length of about 110 km in North of Tehran and soutern of central Alborz with W-E trend (N25˚E) and dipping (30˚NE) is located in western of Mosha Fault.The branch of Chitgar such as Milad and Vardavard Fault in the form of propagation fault is increased toward south. Previous morphotectonical investigation along the North Tehran Fault show that shear of quaternary sedimentation and pressure mechanism with left-lateral component. Determination of seismic parameter and seismic action that result of this fault movement, need to doing paleoseismological investigation. In this text with using stratigraphy correlation method, estimated of subsidence rate is 0.16 mm/yr and logging with ratio and ortho photography method, 3-6 event is determined with 6.4-7.4 magnitude and recurrence time is 3650 yr at Chitgar trench.

The Firouzkuh Fault in most of its extension is located at the southern side of Firouzkuh Valley in west of the Central Alborz. It is a SW – NE prominent structure with a 70 km long on a sinistral –normal fault. It has been known as a south-dipping reverse fault.Paleoseismic analysis and C14 dating along the Firouzkuh left -lateral strike-slip fault indicate that Central Alborz has been shaken by large earthquakes during the Holocene. Here we present the data carried out of one of the two excavated trenches with 40 m long, 2m wide, ~ 4m deep in the east of Firouzkuh, where we found some evidence for last paleoearthquake associated to seismic re-activity on Firouzkuh Fault in the second trench (F2) that dug across a gauge zone. The last event is evidenced by cutting young superficial deposit where this faulted unit stratigrafically covered alluvium deposits yielded dated human bones fragments. The bones found in 60-70cm-deep of trench which a C14age of 1159 ± 28 BP. Regarding to estimated slips per event on paleoseismological log of eastern wall of trench F1, event magnitudes for each paleoearthquakes are M≈7.