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.     

Quench performance and mechanical behavior of the first Fermilab-built prototype high gradient quadrupole for the LHC interaction regions

As part of the US LHC program to provide high gradient superconducting quadrupoles for the LHC interaction regions, a 5.5 meter long prototype magnet has been built and tested horizontally in a production type cryostat at Fermilab. This prototype magnet was used to validate the mechanical and magnetic design, production fabrication and assembly tooling. The first prototype magnet has met the LHC requirements of operating at 215 T/m with excellent magnetic field harmonics. This paper summarizes the test results of this magnet, including quench tests and mechanical behavior over several thermal cycles.     

Phase detector for data-clock recovery circuit

A new type of phase detector which can be used in data-clock recovery circuits is reported. The main feature of the proposed phase detector is that it is free front data dependent jitter, which is the main problem with the Hogge phase detector     

Adaptive radio resource assignment for simultaneous services

An adaptive algorithm for selecting rate matching parameters has been developed to satisfy the operating frame error rate requirements for simultaneous services in 3G Universal Mobile Telecommunications System (UMTS) under Rayleigh fading channels. The results show that the adaptive algorithm can achieve the target error rates for multiplexed services of varying data rates and types, and only requires a few adjustments for convergence.     

Impurity controlled excitations in doped quantum dot exposed to periodic external perturbation

We investigate the excitation behavior of a repulsive impurity doped quantum dot under the influence of an oscillatory external electric field. We have considered Gaussian impurity centers doped at on-center position. The investigation reveals that a variation in the strength and spatial stretch of the dopant causes maximization and minimization in the average excitation rate, respectively. The findings are expected to have important applications involving quantum dot nanodevices.     

An Optimization-Based Algorithm for Shunt Active Filter Under Distorted Supply Voltages

In this paper, an optimization-based control algorithm for the compensation of steady-state load under distorted supply voltages is presented. For balanced and sinusoidal supply voltages, load compensation using shunt active filter produces perfect harmonic cancellation (PHC) and unity power factor (UPF) source currents. However, when the supply voltages are distorted, compensation for PHC will not provide UPF, as the harmonics in the supply voltages are not utilized for delivering the average power. In the same way, to achieve UPF source currents, the compensated source currents should have the same harmonics, unbalance, shape, and be in phase with the respective supply voltages, thereby violating the perfect harmonic cancellation objective. Hence, there should be an optimal operation between these two important compensation characteristics. The optimization-based control algorithm presented in this paper gives the best power factor while satisfying the constraints such as total harmonic distortion limits and average power balance of source currents. It is also flexible to adopt different compensation characteristics based upon the supply voltage conditions. Matlab and its optimization toolbox are used for simulation studies and solving the nonlinear optimization problem, respectively. The algorithm is validated by using a prototype of digital signal processor (TMS320F2812PGFA)-based shunt active power filter. Detailed experimental results are presented.     

Nucleation kinetics of Cu6Sn5 by reaction of molten tin with a copper substrate

The nucleation kinetics of the η-phase (Cu₆Sn₅) intermetallic compound were investigated by hot dipping copper coupons in molten tin for 1 and 2 sec, at temperatures varying from 240°C to 300°C. In the scanning electron microscope (SEM), the Cu₆Sn₅ phase appears as small, rounded bumps of varying sizes, jutting out from the surface of the copper. The experimentally determined nucleation curves show the typical inverse C type behavior with a maximum nucleation rate occurring at an intermediate temperature. The role of surface finish on nucleation rate was also studied. Experimentally determined “effective nucleation rate” per unit area is presented and compared with theoretical predictions over the temperature range investigated. Relevant nucleation models and nucleation energetic parameters are also discussed.     

A framework for statistical wireless spectrum occupancy modeling

In this paper, we propose a novel spectrum occupancy model designed to generate accurate temporal and frequency behavior of various wireless transmissions. Our proposed work builds upon existing concepts in open literature in order to develop a more accurate time-varying spectrum occupancy model. This model can be employed by wireless researchers for evaluating new wireless communication and networking algorithms and techniques designed to perform dynamic spectrum access (DSA). Using statistical characteristics extracted from actual radio frequency measurements, first- and second-order parameters are employed in a statistical spectrum occupancy model based on a combination of several different probability density functions (PDFs) defining various features of a specific spectrum band with several concurrent transmissions. To assess the accuracy of the model, the output characteristics of the proposed spectrum occupancy model are compared with realtime radio frequency measurements in the television and paging bands.     

MXene-Based Anode-Free Magnesium Metal Battery

Rechargeable magnesium batteries (RMBs) are promising next-generation low-cost and high-energy devices. Among all RMBs, anode-free magnesium metal batteries that use in situ magnesium-plated current collectors as negative electrodes can afford optimal energy densities. However, anode-free magnesium metal batteries have remained elusive so far, as their practical application is plagued by low Mg plating/stripping efficiency due to nonuniform Mg deposition on conventional anode current collectors. Herein, for the first time, an anode-free Mg-metal battery is developed by employing a 3D MXene (Ti₃C₂T_x) film with horizontal Mg electrodeposition. The magnesiophilic oxygen and reactive fluorine terminations in MXene enable an enriched local magnesium-ion concentration and a durable magnesium fluoride-rich solid electrolyte interphase on the Ti₃C₂T_x film surface. Meanwhile, Ti₃C₂T_x MXene exhibits a high lattice geometrical fit with Mg (≈96%) to guide the horizontal electrodeposition of Mg. Consequently, the developed Ti₃C₂T_x film achieves reversible Mg plating/stripping with high Coulombic efficiencies (>99.4%) at high-current-density (5.0 mA cm⁻²) and high-Mg-utilization (50%) conditions. When this Ti₃C₂T_x film is coupled with a pre-magnesized Mo₆S₈ cathode, the anode-free Mg-metal full-cell prototype exhibits a volumetric energy density five times higher than its standard Mg-metal counterpart. This work provides insights into the rational design of anode current collectors to guide horizontal Mg electrodeposition for anode-free Mg metal batteries.     

A secure dynamic IP configuration scheme for mobile ad hoc networks

Secure dynamic IP addressing is a prime requirement for unicast communication between authorized hosts in mobile ad hoc networks (MANETs). Recently, several approaches have been proposed for dynamic addressing scheme. However, most of the approaches rely on broadcasting for address solicitation and/or duplicate address detection. As a result, several types of security threats in dynamic IP configuration can be observed. In this paper, we present an ID based dynamic IP configuration scheme that can securely allocate IP addresses to the authorized hosts for a mobile ad hoc network without broadcasting over the entire network. Each host in the MANET can generate an unique IP address from its own IP address for a new host. The proposed scheme provides authentication for address configuration without the help of a trusted third party while taking care of the security-threats associated with dynamic IP configuration. Performance analysis shows that even with added security mechanisms our proposed addressing scheme has fairly good addressing latency and control overhead compared to the similar existing schemes. Moreover, the proposed scheme is able to solve the problem of network partitions and mergers along with the arrival and departure of a host efficiently and securely.