Offline Error Detection in MEDA-Based Digital Microfluidic Biochips Using Oscillation-Based Testing Methodology

Digital microfluidics is an emerging class of lab-on-a-chip system. Reliability is a critical performance parameter as these biochips are employed in various safety-critical biomedical applications. With the introduction of highly scalable, reconfigurable and field programmable Micro-Electrode-Dot-Array (MEDA) architecture, the limitation of conventional DMFBs in varying the droplet size/volume in fine grain manner has been resolved. However, the MEDA-based biochips must be adequately tested upon fabrication to guarantee the correctness of bioassays. In this work, an offline testing approach based on Oscillation-Based Testing (OBT) methodology is presented for MEDA-based digital microfluidic biochips. Various simulations were performed for droplet-electrode short fault model involving single and multiple micro-electrodes. Furthermore, the loss of droplet volume due to the presence of defect was analyzed using COMSOL Multiphysics. The simulation results based on PSpice and COMSOL show that the proposed approach is effective for detecting defects in MEDA-based biochips.     

Cell alignment using patterned biocompatible gold nanoparticle templates

Biocompatible structures are produced for cellular patterning. The biocompatible surfaces are generated to provide protein nonfouling patterns, offering direct communication to the cells for controlling cell adhesion and proliferation. These biofunctional surfaces provide a platform for aligning the cells in the direction of patterns, indicating potential application in the field of tissue engineering.     

Mass transfer on a continuous flat plate moving in parallel or reversely to a free stream in the presence of a chemical reaction

An analysis is made to investigate the mass transfer in two-dimensional boundary layer flow past a flat plate moving in parallel or reversely to a free stream with first order chemical reaction. The similarity transformations are used to transform the governing equations and the reduced nonlinear self-similar ordinary differential equations are solved numerically using a shooting method. The dual solutions of the velocity and concentration distributions are obtained. With increase of the Schmidt number the mass transfer is found to be enhanced for the upper solution branch and reduced for the lower solution branch. The concentration overshoot for constructive chemical reaction is observed, i.e., for constructive reaction mass absorption occurs. Moreover, for destructive chemical reaction the mass transfer increases.     

An Investigation on Turning Hardened Steel Using Different Tool Inserts

Turning of hard materials usually presents poor machinability. However, for high productivity, it is desirable to employ turning of hard materials rather than grinding. In this work, turning of hardened 16MnCrS5 steel with hardness of 43 HRC was explored to judge machining performance with plain and wide-groove-type chip-breaking TiC-coated carbide inserts under dry and wet environmental conditions, different cutting velocity, and feed. Tool wear tests were also done in dry and wet conditions. Satisfactory tool performance was observed under wet condition using TiC-coated plain and wide-groove carbide inserts even at 268 m/min cutting velocity, when dry machining could not be done effectively.     

Built-in Self-test and Defect Tolerance in Molecular Electronics-based Nanofabrics

We propose a built-in self-test (BIST) procedure for nanofabrics implemented using chemically assembled electronic nanotechnology. Several fault detection configurations are presented to target stuck-at faults, shorts, opens, and connection faults in nanoblocks and switchblocks. The detectability of multiple faults in blocks within the nanofabric is also considered. We present an adaptive recovery procedure through which we can identify defect-free nanoblocks and switchblocks in the nanofabric-under-test. The proposed BIST, recovery, and defect tolerance procedures are based on the reconfiguration of the nanofabric to achieve complete fault coverage for different types of faults. We show that a large fraction of defect-free blocks can be recovered using a small number of BIST configurations. We also present simple bounds on the recovery that can be achieved for a given defect density. Simulation results are presented for various nanofabric sizes, different defect densities, and for random and clustered defects. The proposed BIST procedure is well suited for regular and dense architectures that have high defect densities.     

Test Wrapper and Test Access Mechanism Co-Optimization for System-on-Chip

Test access mechanisms (TAMs) and test wrappers are integral parts of a system-on-chip (SOC) test architecture. Prior research has concentrated on only one aspect of the TAM/wrapper design problem at a time, i.e., either optimizing the TAMs for a set of pre-designed wrappers, or optimizing the wrapper for a given TAM width. In this paper, we address a more general problem, that of carrying out TAM design and wrapper optimization in conjunction. We present an efficient algorithm to construct wrappers that reduce the testing time for cores. Our wrapper design algorithm improves on earlier approaches by also reducing the TAM width required to achieve these lower testing times. We present new mathematical models for TAM optimization that use the core testing time values calculated by our wrapper design algorithm. We further present a new enumerative method for TAM optimization that reduces execution time significantly when the number of TAMs being designed is small. Experimental results are presented for an academic SOC as well as an industrial SOC.     

On Using Exponential-Golomb Codes and Subexponential Codes for System-on-a-Chip Test Data Compression

We examine the use of exponential-Golomb codes and subexponential codes can be used for the compression of scan test data in core-based system-on-a-chip (SOC) designs. These codes are well-known in the data compression domain but their application to SOC testing has not been explored before. We show that these codes often provide slighly higher compression than alternative methods that have been proposed recently.     

Synthesis, magnetic and thermoelectric properties of Rh2MO6 (M = Mo, Te, and W) with rutile-related structure

The Rh₂MO₆ compounds with M = Mo, W and Te were synthesized by solid state reaction. The compounds all crystallize in a rutile-type structure. These compounds would be expected to be diamagnetic insulators if the oxidation states were Rh³⁺ and M⁶⁺. In fact, all show relatively high electronic conductivities with Rh₂TeO₆ showing the highest electronic conductivity of ∼500 S/cm at room temperature. Measurable magnetic moments also indicate valence degeneracy between Rh and the M cation. The measured Seebeck coefficients are relatively low and positive indicating hole-type conduction.