Stress distribution variations during nanoindentation failure of hard coatings on silicon substrates

Regarding quality inspection of technologically important nanocomposite hard coatings based on Ti,B,Si,C,and N and bioceramics such as hydroxyapatite that are used in small-scale high-precision devices and bio-implants,it is essential to study the failure mechanisms associated with nanoindentation,such as fracture,delamination,and chipping.The stress imposed by the indenter can affect the fracture morphology and the interfacial fracture energy,depending on indenter shape,substrate type,crystallographic properties,pre-existing flaws,internal microcracks,and pre-strain.Reported here are finite-element-based fracture studies that provide insights into the different cracking mechanisms related to the aforementioned failure process,showing that the fracture morphology is affected by the interaction of different cracking events.The interfacial fracture energy,toughness,and residual stress are calculated using existing models with minor adjustments,and it is found that increasing the indenter sharpness improves the shear stress distribution,making the coating more prone to separation.Depending on the prevailing type of stress,the stress distribution beneath the depression results in either crack formation or a dislocation pile-up leading to strain hardening.Different forms of resistances resulting from the indentation process are found to affect the tip–sample conduction,and because of its stronger induced plasticity than that of a Berkovich indenter tip,a sharper cube-corner tip produces more resistance.

Magneto-thermo-elastic waves in an infinite perfectly conducting elastic solid with energy dissipation

The generalized thermo-elasticity theory, i.e., Green and Naghdi （G-N） Ⅲ theory, with energy dissipation （TEWED） is employed in the study of time-harmonic plane wave propagation in an unbounded, perfectly electrically conducting elastic medium subject to primary uniform magnetic field. A more general dispersion equation with com- plex coefficients is obtained for coupled magneto-thermo-elastic wave solved in complex domain by using the Leguerre＇s method. It reveals that the coupled magneto-thermoelastic wave corresponds to modified dilatational and thermal wave propagation with finite speeds modified by finite thermal wave speeds, thermo-elastic coupling, thermal diffusivity, and the external magnetic field. Numerical results for a copper-like material are presented.

基于液位测量系统的定时器的开发（英文）

本文基于液位测量系统设计开发了定时器,其中IC555用于不稳定模式。使用数字存储振荡器(DSO)测量的定时器输出波形接通时间的脉冲宽度,即电容器充电时间(T_C),与同轴圆柱形电容换能器的电容成线形比例,且该电容随着液位的变化而线性变化。因此,我们获得了电容器充电时间与液位的线性关系,该设计的优点是输入-输出具有线性关系,尺寸小,便于携带,成本低,且不受环境温度影响,它还可用于测量各种工业中液体或固体的介电常数。

An Efficient Nonuniform Cosine Modulated Filter Bank Design Using Simulated Annealing

In this paper, a new approach for the design of non-uniform frequency spacing filter bank using Simulated Annealing has been presented. The filter bank structure is obtained by merging the relevant bands of a uniformly shifted filter bank with integer sampling factors. The design problem is formulated as a single objective unconstrained optimization problem for reducing the amplitude distortion of the overall filter bank for a specified pass-band ripple and stop-band attenuation of the prototype filter. The prototype filter coefficients are optimized using block update method to reach global optimum very quickly and the near perfect reconstruction of the filter bank is also preserved. Simulation results demonstrate that the linear-phase non-uniform filter banks designed by the proposed method have small amplitude distortions and aliasing distortions. Using this technique to minimize design objective is suitable for filter banks applied in sub-band filtering because linear phase property is assured here.

Parity generator and parity checker in the modified trinary number system using savart plate and spatial light modulator

The parity generators and the checkers are the most important circuits in communication systems. With the development of multi-valued logic (MVL), the proposed system with parity generators and checkers is the most required using the recently developed optoelectronic technology in the modified trinary number (MTN) system. This system also meets up the tremendous needs of speeds by exploiting the savart plates and spatial light modulators (SLM) in the optical tree architecture (OTA).

Trinary registers and counters using savart plate and spatial light modulator for optical computation in multivalued logic

Registers and counters are the most important devices in any system of computations.In this paper we have communicated the trinary registers and counters in modified trinary number(MTN) system.It is suitable for the optical computing and other applications in multivalued logic system.Here the savart plate and spatial light modulator(SLM) based optoelectronic circuits have been used to exploit the optical tree architecture(OTA) in optical interconnection network.

Trinary magnitude comparator using SLM based Savart plate

The demand of present technology inviting the popularity of multivalued optical computation system to coup up with the latest scenario of ultrahigh processing speed and handling large amount of data The magnitude comparator is the heart of the arithmetic and logic unit(ALU)in any logical processing and computing system.In this paper,a trinary magnitude comparator circuit has been proposed and implemented with modified trinary number(MTN)system.Optical tree architecture(OTA)of the proposed circuit has been realized reasonably using Savart plate and spatial light modulators(SLM).A simulation algorithm has also been developed and implemented to prove the authenticity of the proposed circuit through the simulation.

Self-capacitance grading approach to suppress winding resonance in EHV transformers under oscillatory terminal disturbances

Interleaving of the high-voltage winding turns is a widely-accepted method for restraining the surge voltage stresses in extra high voltage(EHV)transformers.Reduction of voltage stresses under external surge is attributed by the increase in the self-capacitance of the interleaved winding disks.However,the apparent benefit of interleaving may be counterpoised by a significant decrease of natural frequency of windings,which in turn,may force a winding to resonate under external surges.Winding resonance is particularly noticeable when uniform interleaving is adopted for the whole winding,uniform interleaving attributes a unique natural frequency to all interleaved coils and consequently,the collective resonance of the winding disks is plausible.Uniform interleaving in large EHV transformers therefore leads to complications and the windings reportedly exhibit an unexpectedly poor surge voltage response because of such internal resonances.This study describes a novel concept termed as‘graded interleaving’for EHV transformer windings to overcome resonance and to achieve an improved response against surge voltage.The performance of the proposed winding was tested on a 132/33 kV two-winding transformer with a tap changer using EMTP(ATP)simulations with encouraging results.Manufacturing and real-time implementation feasibility of the winding were verified with transformer manufacturers.