An efficient small‐delay faults simulator based on critical path tracing

Testing for small‐delay defects (SDDs) has become an important component of integrated circuit testing. In this paper, an efficient small‐delay fault simulator, a hybrid method combining forward serial simulation and backward critical path tracing simulation for SDDs is proposed, which aims to determine the coverage of small‐delay defects for a given test set fast and accurately. In our proposed method, a unit delay model is employed, and reconvergent sensitization as well as hazard‐based detection is considered. Signal waveforms are expressed by bitmap data forms. In addition to providing an accurate result for fault simulation, the proposed simulator can well assist test generation. Experimental results demonstrate that the proposed simulator can further accelerate the simulation by one or two orders of magnitude compared with previous works. Copyright © 2014 John Wiley & Sons, Ltd.     

Multiobjective optimization of product and process networks: General modeling framework,efficient global optimization algorithm,and case studies on bioconversion

A comprehensive optimization model that can determine the most cost‐effective and environmentally sustainable production pathways in an integrated processing network is needed, especially in the bioconversion space. We develop the most comprehensive bioconversion network to date with 193 technologies and 129 materials/compounds for fuels production. We consider the tradeoff between scaling capital and operating expenditures (CAPEX and OPEX) as well as life cycle environmental impacts. Additionally, we develop a general network‐based modeling framework with nonconvex terms for CAPEX. To globally optimize the nonlinear program with high computational efficiency, we develop a specialized branch‐and‐refine algorithm based on successive piecewise linear approximations. Two case studies are considered. The optimal pathways have profits from ?$12.9 to $99.2M/yr, and emit 791 ton CO₂‐eq/yr to 31,571 ton CO₂‐eq/yr. Utilized technologies vary from corn‐based fermentation to pyrolysis. The proposed algorithm reduces computational time by up to three orders of magnitude compared to general‐purpose global optimizers. © 2014 American Institute of Chemical Engineers AIChE J, 61: 530–554, 2015     

Smoke and toxicity suppression by zinc salts in flame‐retardant polyurethane‐polyisocyanurate foams filled with phosphonate and chlorinated phosphate

Three types of zinc salts, ZnAl₂O₄, ZnFe₂O_4, and Zn₂SiO_4, were prepared by coprecipitation. Potential smoke and toxicity suppression by zinc salts in flame‐retardant polyurethane‐polyisocyanurate foams (FPUR‐PIR) with dimethylmethylphosphonate (DMMP) and tris (2‐chloropropyl) phosphate (TCPP) were investigated. The crystal structure and dispersity of zinc salts in FPUR‐PIR were characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Smoke density, flame retardancy, and thermal degradation were studied using smoke density rating (SDR), limiting oxygen index (LOI), the cone calorimeter test, and thermogravimetry coupled with FTIR spectrophotometry (TGA‐FTIR). The results indicated that pure zinc salts were obtained and evenly dispersed on the cell wall of FPUR‐PIR. SDR and the specific extinction area (SEA) were significantly decreased, the time to second heat release rate peak (pk‐HRR) of FRUP‐PIR was delayed after incorporation of the zinc salts; zinc salts partially inhibited phosphorus oxide release into the gas phase, enhanced the condensed phase effect of phosphorus, reduced, and prolonged the release of isocyanate compound and hydrogen cyanide from FRUP‐PIR; due to an increase in the amount of char residues, which indicated the suppression of smoke and toxicity volatiles. ZnFe₂O₄ resulted in better char formation at the initial degradation stage of FPUR‐PIR, and ZnAl₂O₄ retained more phosphorus in the solid phase at higher temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41846.     

Acetamide‐modified hyper‐cross‐linked resin: Synthesis,characterization, and adsorption performance to phenol from aqueous solution

Acetamide‐modified hyper‐cross‐linked resin, HCP‐HMTA‐AA, was prepared and its adsorption performance was evaluated using phenol as the adsorbate. The prepared HCP–HMTA–AA owned predominant micro/mesopores and medium polarity, making it possess a superior adsorption to phenol as compared with polystyrene (PS), chloromethylated polystyrene (CMPS), hyper‐cross‐linked polymer (HCP) and amino‐modified hyper‐cross‐linked resin (HCP–HMTA). The adsorption enthalpy was ?99.56 kJ/mol at zero fractional loading, multiple hydrogen bonding contributed to such a great adsorption enthalpy and an approximately planar hexahydric ring was formed between acetamide of HCP–HMTA–AA and phenol. The dynamic capacity of phenol on HCP–HMTA–AA was 291.3 mg/g at a feed concentration of 946.2 mg/L and a flow rate of 48 mL/h and the resin column was almost regenerated by a mixed solvent including 50% of ethanol (v/v) and 0.01 mol/L of sodium hydroxide (w/v). HCP–HMTA–AA was repeatedly used for five times and the equilibrium adsorption capacity for the five time reached 94.2% of the equilibrium adsorption capacity for the first time. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41597.     

A novel method of making PVF porous foam without using the pore forming agent

Different with the conventional method of manufacturing poly(vinyl formal) (PVF) porous foam by using the pore‐forming agents such as wheat or potato starches, a novel method without using the pore‐forming agent is introduced in this article. Through the help of images taken by a scanning electron microscope, the formation process of the present PVF foam will be discussed in terms of the spinodal decomposition (SD) phase separation principle. Additionally, the effect of poly(vinyl alcohol) concentration and reaction temperature on the pore structure of the PVF foam will be investigated. Moreover, the water adsorption capacities of the PVF foams obtained by the present method will be studied in details through the analyses of pore‐size distribution, mechanical modulus, and thermal property. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41270.     

Fullerene-like Re-Doped MoS2 Nanoparticles as an Intercalation Host with Fast Kinetics for Sodium Ion Batteries

Sodium ion batteries (SIBs) are considered as a promising alternative to threaten the reign of lithium ion batteries (LIBs) among various next-generation rechargeable energy storage systems, including magnesium ion, metal air, and metal sulfur batteries. Since both sodium and lithium are located in Group 1 of the periodic table, they share similar (electro)chemical properties with regard to ionization pattern, electronegativity, and electronic configuration; thus the vast number of compounds developed from LIBs can provide guidance to design electrode materials for SIBs. However, the larger ionic radius of the sodium cation and unique (de)sodiation processes may also lead to uncertainties in terms of thermodynamic or kinetic properties. Herein, we present the first construction of SIBs based on inorganic fullerene-like (IF) MoS₂ nanoparticles. Closed-shell-type structures, represented by C₆₀ fullerene, have largely been neglected for studies of alkali-metal hosting materials due to their inaccessibility for intercalating ions into the inner spaces. However, IF-MoS₂, with faceted surfaces, can diffuse sodium ions through the defective channels, thereby allowing reversible sodium ion intercalation/deintercalation. Interestingly, Re-doped MoS₂ showed good electrochemical performances with fast kinetics (ca. 74 mA h g⁻¹ at 20 C). N-type doping caused by Re substitution of Mo in IF-MoS₂ revealed enhanced electrical conductivity and an increased number of diffusion defect sites. Thus, chemical modification of fullerene-like structures through doping is proven to be a promising synthetic strategy to prepare improved electrodes.     

Effects of SiNx interlayer on characterisation of amorphous diamond-like carbon films

The magnetron sputtering amorphous diamond-like carbon film is successfully deposited by SiN_x interlayer approach. The scanning electron microscopy study reveals the creation of high uniform surface micrograph diamond-like carbon films with SiN_x interlayer. For comparison, diamond-like carbon films with different interlayers are also grown. The Raman spectra are analyzed in order to characterize the stressed induce peak shifts of the films. The interactions of C atom with Si(100) and SiN_x surface are studied by density functional theory simulation. The effects of interlayers on the films deposition and the considering deposition mechanism are discussed. It is suggested that the diamond-like carbon and SiN_x bilayer structure can help to render applications in protective coatings and high quality silicon on diamond related radiation tolerance devices.     

50th Anniversary Article: Seeing Stresses through the Thermoelastic Lens—A Retrospective and Prospective from an Australian Viewpoint

Thermoelastic stress analysis (TSA) has been around for the past 30 years, but to date, it is still a very much underrated and under‐utilised experimental technique. Although there are devoted groups of practitioners in some industries, this technology is not well known within the aerospace sector. In contrast, the Aerospace Division of the Defence Science and Technology Organisation (DSTO) in Australia has been in the forefront of this technology for some time, achieving many pioneering feats. This paper gives a brief introduction to the development of this technology from a historical perspective, then focuses on a number of innovations that have stemmed from DSTO, including the development and application of the world's first focal plane array based TSA system and, more recently, the development of small and robust microbolometer based systems. For the latter, it is shown that despite nominally poorer temperature sensitivities, they make ideal TSA devices and can in some cases outperform their much more expensive photon detector counterparts. Because of this, together with the enormous practical advantages of microbolometers, the future of TSA is shown to be brighter than ever. Specifically, it is argued that such TSA systems can play a major role in the pervasive and persistent surveillance of full scale fatigue testing of aircraft structures. By detecting both design and developing faults early, it can effectively relieve cost and schedule penalties that are often associated with unanticipated failures. To realise this capability, integration of this technology with autonomous systems will be important, and some preliminary but promising results from a technology demonstrator program are presented.