Fractional Differential Equations

The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

http://ieeexplore.ieee.org/iel5/5610941/5624686/05624745.pdf

Power electronics

System Identification I

Consider the function defined for $\alpha _{1},\ \alpha _{2} \in \mathbb{R}$ (α 1 2 +α 2 2 ≠ 0) and $\beta _{1},\beta _{2} \in \mathbb{C}$ by the series 

$$\displaystyle{ E_{\alpha _{1},\beta _{1};\alpha _{2},\beta _{2}}(z) \equiv \sum _{k=0}^{\infty } \frac{z^{k}} {\varGamma (\alpha _{1}k +\beta _{1})\varGamma (\alpha _{2}k +\beta _{2})}\ \ (z \in \mathbb{C}). }$$

(6.1.1)

Such a function with positive α 1 > 0, α 2 > 0 and real $\beta _{1},\beta _{2} \in \mathbb{R}$ was introduced by Dzherbashian [Dzh60].

Multi-index Mittag-Leffler Functions

Sub-criticality, criticality, and reactivity are the terms which are not annunciated in Indian PHWRs (Pressurised Heavy Water Reactors) and are thus not very clear to the reactor operators. These parameters are prime movers defining nuclear reactor and should be annunciated in control room by simple means to aid operator to view reactivity excursions while in power operation or during shutdown maintenance. A very novel circuit of a hardwire scheme to solve the coupled neutron kinetics is presented and its output is compared against analytical solutions. This scheme does not require any estimation technique and is robust as the instrument is based on basic reactor governing laws. This instrument is able to show the transients in reactivity as well as steady state values and is aimed for all Indian PHWRs for multi-decade operation. This technique is tunable for any research reactor or fast reactor too.

A new hardwire circuit for metering reactivity

Strongly non-Newtonian fluids namely, aqueous gels of starch, are shown to exhibit visco-elastic behavior, when subjected to a load. We study arrowroot and potato starch gels. When a droplet of the fluid is sandwiched between two glass plates and compressed, the area of contact between the fluid and plates increases in an oscillatory manner. This is unlike Newtonian fluids, where the area increases monotonically in a similar situation. The periphery moreover, develops an instability, which looks similar to Saffman Taylor fingers. This is not normally seen under compression. The loading history is also found to affect the manner of spreading. We attempt to describe the non-Newtonian nature of the fluid through a visco-elastic model incorporating generalized calculus. This is shown to reproduce qualitatively the oscillatory variation in the surface strain.

https://iopscience.iop.org/article/10.1088/1742-6596/319/1/012006/pdf

Spreading of Non-Newtonian and Newtonian Fluids on a Solid Substrate under Pressure

The applications of microwaves in engineering has been fast expanding, one such area is micromachining and micro-fabrication. A series of experiment with different types of concentrator (steel, copper and nichrome) wascarried out. Different machining conditions like variable power, location and movement were considered. The drilled hole shows development of three differentheat affected zones (HAZs). The performance of the process was evaluated in term of the residue diameter, HAZ diameter and the hole diameter. Energy Dispersive Spectroscopy (EDS) and field emission scanning electron microscope (FESEM) were used to assess the zone and damage of the monopole concentrator used as drilling tool. The drill bit damage in its length was controlled with careful selection of process parameters. An optimum processing condition was determined experimentally, for minimum residue generation, minimum HAZ and minimum oversize of drilled holes. The depth of through hole in perspex material was maintained constant at 2 mm.

/pdf/performance-of-monopole-concentrator-during-microwave-5g26enmk52.pdf

Performance of Monopole Concentrator during Microwave Drilling of Perspex

The surface preparation of shiny stainless steels is a must for applying esthetic paints, effective functional plasma spray coating, laser cladding, welding, etc., applications. The current work aims for effective surface roughening and erosion MRR of SS 304 work surface using SiC abrasive jet erosion and optimization of the process parameters. The response surface approach is used to design and conduct the studies using the Box–Behnken design method. The surface topography of the eroded surfaces is examined by a 2D profilometer, 3D profilometer, and scanning electron microscope (SEM). The abrasive grit size and working gas pressure greatly affect the surface roughness of SS 304 samples. The influence of the process parameters on the variation of these topographical features is analyzed and confirmed. The working jet pressure is seen to significantly impact erosion MRR. The lower working gas pressure shows a typical influence on Ra (surface preparation) and as pressure increases, erosion MRR rises, and the surface preparation mode shifts to the erosion metal removal/cutting zone. The quality of SS 304 surface prepared from SiC abrasive jet impact is characterized by 3D profilometry.

/pdf/surface-preparation-for-coating-and-erosion-mrr-of-ss-304-25rju6wb.pdf

Surface Preparation for Coating and Erosion MRR of SS 304 Using Silicon Carbide Abrasive Jet

In this paper a master-slave approach to chaos synchronization in commensurate fractional order FO Lu system has been studied via optimally designed fractional order Proportional Integral Derivative PID Controller. An optimization frame work based on integral time indices has been considered for tuning the unknown parametric constants of FOPID controller. The optimization task was carried out using bees swarm intelligent based Artificial Bee Colony algorithm. A comparative study based on conventional PID control scheme has also been performed to highlight the advantage of using fractional order controller for fractional order systems. Simulation results presented for synchronization of chaos in two Lu systems supports the claim for proposed approach.

Shantanu Das

Papers

A new hardwire circuit for metering reactivity

Spreading of Non-Newtonian and Newtonian Fluids on a Solid Substrate under Pressure

Performance of Monopole Concentrator during Microwave Drilling of Perspex

Surface Preparation for Coating and Erosion MRR of SS 304 Using Silicon Carbide Abrasive Jet

Chaos Synchronization in Commensurate Fractional Order Lü System via Optimal PIλ Dμ Controller with Artificial Bee Colony Algorithm