in an electrically anisotropic media, current density  is not aligned with the electric field  and varies with the e-field direction. this can be considered as the spatial aliasing effects aroused by the subsurface structures whose individual dimensions are smaller than the inductive length scale of diffusively propagating em fields. the role of these structures is particularly significant in t...

With the development of oil drilling in depth, strata are more ancient and abrasive. The Rate Penetration (ROP) is low conventional methods, Positive Displacement Motor (PDM) matching PDC bits often used to improve it. However, application excessive Weight on Bit (WOB) would easily lead PDM brake, over-standard well inclination, bit wearing aggravation other bad phenomena. Moreover, ROP improvi...

In latest years small scale machining has been widely used in advanced engineering applications such as medical and optical devices, micro- nano-electro-mechanical systems. micromachining of metals, a depth cut becomes usually smaller than an average crystal size polycrystalline structure; thus, the cutting process zone can be localized fully indoors single grain. Due to crystallographic anisot...

Magnetic nanodiscs are fabricated by depositing cobalt onto 10–30 nm diameter silicon nanopillars, which were prepatterned using gold colloids as etch masks. The magnetic anisotropy energy of individual nanodiscs is studied by measuring the angular dependence of switching field using the micro-SQUID technique. The Stoner–Wohlfarth model, describing the magnetization reversal by unifom rotation,...

the main task of drilling the formation by the bit is done via scraping, crushing and grinding. discharging the fluid from the bit nozzles is done with high pressure which assists to break the rocks. different parameters affect the bit selection and design for each drilling formation, but the most important one is drillability that depends on hardness of the formation. in this paper, the design...

An ultra-low power area-efficient fully differential multi-bit quantizer used in Sigma-Delta modulator (SDM) is presented. The quantizer is named as capacitor-string area-efficient (CSAE) quantizer since instead of the typical resistor string, it employs a capacitor string to avoid static power consumption. Furthermore, a novel circuit configuration with saving half number of comparators is app...

Cohesive-frictional soils are widely used in the construction of embankment structures and due to the method of construction, i.e. applying compactive efforts in the vertical direction in these cases, the occurrence of anisotropy in the soil strength and permeability seems to be inevitable. In this study, attempts have been made to evaluate the shear strength of c-f soils through modifying a l...