A study on remanufacturing possibility of a product

With the intensification of Globalization, customers’ environment-friendly attitude and stringent environmental regulations, the manufacturers have been orienting their manufacturing and other value additive processes towards the development of more environment-friendly products and use of relevant processes including taking back of used products after their end-of-use or end-of-life from the end users. Remanufacturing is one of the prominent and popular options. Remanufacturing perhaps has drawn maximum attention because of its economic viability and environmental cleanliness. The remanufacturing operation depends upon the quality and quantity of the used. Better the quality lesser the remanufacturing cost. A remanufacturer is unaware about the condition of used product before its acquisition. It may also be noted that the remanufactured product may be taken after a period of its use by users. So it is really difficult to judge how many cycles does the product go for remanufacturing. This has drawn the attention of the authors and the problem is studied with developing some mechanism on the possible frequency of the remanufacturing of a new product. This paper is a study report on this area of research which is expected to contribute immensely to the remanufacturing business.

     

Performance analysis of wireless communication system over nonidentical cascaded generalised gamma fading channels

Multiplicative fading statistics usually encountered in different radio propagation environments. In this context, we evaluate and analyse the performance of a wireless communication system over the nonidentical cascaded generalised Gamma Fading Channels, also known as generalised Bessel‐K fading channel. To this end, the closed‐form expressions for the amount of fading (AOF), the outage probability (OP), the average symbol error probability (SEP), and the channel capacity are derived. In addition approximate expressions for the average SEP with maximal ratio combining (MRC) diversity are also provided. The low‐ and high‐power solutions for the channel capacity are also provided. Furthermore, simplified asymptotic average SEP expressions for MRC and selection combining (SC) are presented to gain the system performance with diversity. The proposed methodologies provide more flexibility to accommodate different radio propagation scenarios. To examine the accuracy of the proposed solutions, numerical and simulation results are compared and shown to fit for variety of fading parameters.     

Centralized sliding mode frequency regulation approach for an uncertain islanded micro grid integrated with disturbance observer

This paper proposes a novel secondary frequency regulation technique for an uncertain islanded micro grid (MG). The major motivation of the work is to integrate the intrinsic robustness of the sliding mode control scheme with the disturbance observer to estimate and alleviate the unknown mismatched uncertainties caused by renewable resources and load variations. To this end, a dynamical sliding manifold is first utilized and then a control law is derived with Lyapunov's method which stabilizes the MG dynamics. Moreover, in order to ensure faster time domain responses of the closed‐loop system, we employ a power rate reaching law in our proposed control design. Thereafter, the performances of the introduced control strategy are tested on an islanded MG using MATLAB/Simulink, and robustness analysis is also carried out by considering five different case studies. Further, in contrast to the existing approaches such as robust H _∞ and robust PID control, the proposed strategy renders appealing time domain characteristics such as settling time, peak overshoot, and integral absolute frequency error.     

Synthesis of a New Robust Exponential Sliding Mode Differentiator with its Observer Applications

This paper proposes a new robust exponential sliding mode differentiator for estimating the (n ? 1) derivatives of a non‐linear function. Finite time convergence, robustness, and exactness are also ensured analytically with the proposed methodology. In addition, the results of the proposed sliding mode differentiator are extended to derive theorems for the novel state (SO) and extended state observers (ESO), which would estimate the system states as well as uncertainties recursively in finite time. Finally, three examples are implemented to validate the proposed methodologies and the obtained simulations are compared with the previously developed methods in literature.     

On machining of hard and brittle materials using rotary tool micro-ultrasonic drilling process

The present paper reports on a recently developed rotary tool micro-ultrasonic drilling (RT-MUSD) process. The RT-MUSD process was utilized for machining of micro-holes in zirconia, silicon and glasswork materials. The effects of work material properties on the performance characteristics (material removal rate (MRR), depth of hole and hole overcut) of RT-MUSD process were investigated by varying the power rating, rotation speed, abrasive size and slurry concentration. Additionally, machined micro-holes and tool surface were analyzed considering microscopic images. The experimental results revealed that the MRR and depth of hole increased by increasing the power rating. An increase in rotation speed up to 300 rpm, abrasive size up to #1200 mesh and concentration up to 20% increased the MRR, depth of hole and decreased hole overcut. The maximum machining rate and hole overcut were observed during machining of silicon followed by glass and zirconia. The fracture toughness and hardness of the work material affected the MRR and tool wear, respectively. Pure brittle fracture mode of material removal was observed in all the work materials during RT-MUSD process. Eventually, the RT-MUSD process was optimized using desirability approach and a micro-hole of depth 4355 µm was achieved using optimal parameter settings.     

On effect of tool rotation on performance of rotary tool micro-ultrasonic machining

The present research paper is based on a comparative study of stationary tool micro-ultrasonic machining (STMUSM) and rotary tool micro-ultrasonic machining (RTMUSM). Microchannels were developed on glass work material by using both processes. The effect of tool rotation on the performance of micro-USM was investigated. The performance of both processes was compared on the basis of material removal rate (MRR) and depth of channel (DOC) as response characteristics. The power rating, work feed rate, concentration of abrasive slurry, and abrasive mesh size were chosen as variable input process parameters in this investigation. The form accuracy of the fabricated microchannels was analyzed with the help of imaging technique. Also, a qualitative analysis of tool wear was carried out with the help of microscopic images. The experimental results revealed that the tool rotation significantly improved the performance of micro-USM. The RTMUSM resulted in 155% and 147% higher MRR and DOC as compared to STMUSM. The tool wear was also found to be lesser in RTMUSM as compared to STMUSM and as a result of that form accuracy of machined microchannels improved.     

Homogeneous and polymorphic transformations to ordered intermetallics in nanostructured Au–Cu multilayer thin films

Journal of Materials Science - Atomic arrangements in the nanostructured grains and interfaces of thermally evaporated Au/Cu multilayer thin films on polycrystalline Si substrate have been explored...     

Linearization of Photonic Link Based on Phase-Controlled Dual Drive Dual-Parallel Mach–Zehnder Modulator

Wireless Personal Communications - Wireless sensor network will be the dominating field in the future era. Right now it goes from the transformation phase. It unfolds its capacity and sort out its...     

Blind Signal Modulation Recognition through Density Spread of Constellation Signature

Wireless Personal Communications - Cluster analysis is a commonly used technique by investors to create a diversified portfolio. The approach aims at maximizing returns for a tolerable degree of...