Multi-Cycle Test with Partial Observation on Scan-Based BIST Structure

Field test for reliability is usually performed with small amount of memory resource, and it requires a new technique which might be somewhat different from the conventional manufacturing tests. This paper proposes a novel technique that improves fault coverage or reduces the number of test vectors that is needed for achieving the given fault coverage on scan-based BIST structure. We evaluate a multi-cycle test method that observes the values of partial flip-flops on a chip during capture-mode. The experimental result shows that the partial observation achieves fault coverage improvement with small hardware overhead than the full observation.2011 Asian Test Symposium (ATS), 20-23 Nov. 2011, New Delhi, Indi

On Flip-Flop Selection for Multi-cycle Scan Test with Partial Observation in Logic BIST

Multi-cycle test with partial observation for scan-based logic BIST is known as one of effective methods to improve fault coverage without increase of test time. In the method, the selection of flip-flops for partial observation is critical to achieve high fault coverage with small area overhead. This paper proposes a selection method under the limitation to a number of flip-flops. The method consists of structural analysis of CUT and logic simulation of test vectors, therefore, it provides an easy implementation and a good scalability. Experimental results on benchmark circuits show that the method obtains higher fault coverage with less area overhead than the original method. Also the relation between the number of selected flip-flops and fault coverage is investigated.27th IEEE ASIAN TEST SYMPOSIUM (ATS\u2718), 15-18 October 2018, Hefei, Chin

A Scan-Out Power Reduction Method for Multi-Cycle BIST

High test power in logic BIST is a serious problem not only for production test, but also for board test, system debug or field test. Many low power BIST approaches that focus on scan-shift power or capture power have been proposed. However, it is known that a half of scan-shift power is compensated by test responses, which is difficult to control in those approaches. This paper proposes a novel approach that directly reduces scan-out power by modifying some flip-flops\u27 values in scan chains at the last capture. Experimental results show that the proposed method reduces scan-out power up to 30% with little loss of test coverage.2012 IEEE 21st Asian Test Symposium, 19-22 Nov. 2012, Niigata, Japa

A universal characterization method on viscous materials using depth sensing indentation

Miniaturisation of devices and a paradigm shift toward using compliant material require small scale characterisation techniques such as nanoindentation [1]. Initial non-conformity of contact and delayed elasticity on the unloading curve are not currently taking into account in nanoindentation methods [2, 3], where the unloading curve is seen fully elastic. A different approach has been taken which considers actual localised deformation during nanoindentation, thus the proposed method [4] is able to acquire untainted elastic or viscoelastic response data. The method, validated for both viscous and non-viscous materials, takes into account the correction of the stiffness associated with the delayed elasticity at initial unloading and determines modulus with less variability even if testing conditions are non-quasi-static. The key step in the methodology is to account for initial conformity of the contact, the nose-out phenomena and delayed elasticity. Thus a full elastic point (FEP) is determined as seen in the figure 1. Traditionally to eliminate the initial delayed elastic response a multi-cycle approach was needed, whereas in our method any materials, even viscous, can be tested under any test conditions in a single loading-unloading cycle. The algorithm is universally applicable. Experiments were conducted on six different viscous materials under single and multi cycle loading conditions to validate our method to existing ones [2–3]. Multi-cycle test on PET & PEN are reported in figure 2. It was found that except for rubber all the different materials studied by using just a single-cycle, our method determined values equally well as previous Oliver and Pharr method [2] with less variation. For multi-cycle tests our method is capable of producing results as good as the fourth-cycle of Feng’s method [3], thus time and cost of experimentation can be reduced. So this method becomes appropriate as a standardised technique, and also for the characterisation of polymers which have been an issue in the past

Kinetic modeling of CO assisted passive NOx adsorption on Pd/SSZ-13

Passive NOx adsorption (PNA) has been recently developed as a promising technology for controlling the NOx emissions during the cold start period. In this work, we illustrate a CO-assisted mechanism by combining experimental and kinetic modeling studies. Pd/SSZ-13 has been synthesized, characterized and evaluated as a PNA in low-temperature NOx adsorption and temperature program desorption cycles, to represent multiple cold start periods. The gas compositions were also systemically changed, where both the effect of varying NOx and CO feed was evaluated in the presence of high water and oxygen contents. A kinetic model was developed to simulate the profiles of NO and NO2, including three initial Pd sites (Z-Pd(II)Z-, Z-[Pd(II)OH]+ and PdO). It is concluded from XPS and in situ DRIFTS experiments, flow reactor measurements and modelling observations that CO reduces Pd(II) species to Pd(I)/Pd(0) species, which increases the stability of the stored NOx species, resulting in a release above the urea dosing temperature. The model could well describe the experimental features, including the effect of CO. In addition, the model was used for full-scale catalytic converter simulations

Prospects of Al2O3 and MgAl2O4-Supported CuO Oxygen Carriers in Chemical-Looping Combustion (CLC) and Chemical-Looping with Oxygen Uncoupling (CLOU)

The chemical-looping combustion (CLC) and chemical-looping with oxygen uncoupling (CLOU) processes are attractive solutions for efficient combustion with direct separation of carbon dioxide. In this work, the feasibility of CuO supported on Al2O3 and MgAl2O4 for CLC and CLOU processes is investigated. The oxygen carriers were produced by freeze-granulation and calcined at 950 and 1050 degrees C. The chemical-looping characteristics were evaluated in a laboratory-scale fluidized bed at 900 and 925 degrees C under alternating reducing and oxidizing conditions. Tendencies toward agglomeration, defluidization, and loss of active phase were analyzed by changing the experimental process variables, such as reaction time, temperature, and reducing and inert environments. Complete conversion of methane was obtained for all oxygen carriers investigated in this work Three out of four oxygen carriers also featured the rapid release of oxygen in an inert environment (CLOU). In the case of Al2O3) as support, a CLC and a CLOU oxygen carrier were obtained depending on the calcination temperature. In addition, analyses of the CuO-Al2O3 phase equilibria system under oxidizing and reducing conditions have been carried out. At the investigated temperatures, it is inferred for the case of Al2O3 as support that part of the active phase (either CuO or CuAl2O4 is bound as CuAlO2 during incomplete reduction with slow kinetics for reoxidation. However, when complete reduction is attained, the original active phase composition is rejuvenated upon oxidation. As a result, the use of CuAl2O4 is suggested for CLC processes from the point of agglomeration and attrition-free functioning of the oxygen carrier. In the case of MgAl2O4 as support, the oxygen carrier exhibited a stable oxygen-releasing behavior due to the existence of relatively intact CuO. Together with the absence of agglomeration and major morphological changes, the use of MgAl2O4-supported CuO is suggested as a suitable oxygen carrier for CLOU processes

Insight into CO induced degradation mode of Pd/SSZ-13 in NOx adsorption and release: Experiment and modeling

Passive NOx adsorption (PNA) on Pd zeolites is an important technique to remove NOx during the cold start of the engine. However, the stability of Pd zeolites under high concentrations of CO is still challenging in multiple cold starts of an engine. Herein, we illustrate the CO-induced degradation mechanism of Pd zeolite by combining experiments and kinetic models. Pd/SSZ-13 has been used in multicycle processes containing NOx adsorption at low temperature and temperature programmed desorption, which represents the PNA degradation in multiple cold start periods. A kinetic model was developed to describe the NOx storage and degradation behavior of Pd/SSZ-13. Both experimental and modelling observations suggested that two Pd sintering modes are occurring under high CO concentration (4000 ppm), namely Ostwald ripening and particle migration. Apart from the degradation behavior, this model is also adequate for describing multi-cycle NOx storage and release behavior under low CO concentration

Comparative analysis of battery electric vehicle thermal management systems under long-range drive cycles

Due to increasing regulation on emissions and shifting consumer preferences, the wide adoption of battery electric vehicles (BEV) hinges on research and development of technologies that can extend system range. This can be accomplished either by increasing the battery size or via more efficient operation of the electrical and thermal systems. This study endeavours to accomplish the latter through comparative investigation of BEV integrated thermal management system (ITMS) performance across a range of ambient conditions (-20 °C to 40 °C), cabin setpoints (18 °C to 24 °C), and six different ITMS architectures. A dynamic ITMS modelling framework for a long-range electric vehicle is established with comprehensive sub models for the operation of the drive train, power electronics, battery, vapor compression cycle components, and cabin conditioning in a comprehensive transient thermal system modelling environment. A baseline thermal management system is studied using this modelling framework, as well as four common thermal management systems found in literature. This study is novel for its combination of comprehensive BEV characterization, broad parametric analysis, and the long range BEV that is studied. Additionally, a novel low-temperature waste heat recovery (LT WHR) system is proposed and has shown achieve up to a 15% range increase at low temperatures compared to the baseline system, through the reduction of the necessary cabin ventilation loading. While this system shows performance improvements, the regular WHR system offers the greatest benefit, a 13.5% increase in cold climate range, for long-range BEV drive cycles in terms of system range and transient response without the need for additional thermal system equipment