Avoiding game‐tree pathology in 2‐player adversarial search

Adversarial search, or game‐tree search, is a technique for analyzing an adversarial game to determine what moves a player should make in order to win a game. Until recently, lookahead pathology (in which deeper game‐tree search results in worse play) has been thought to be quite rare. We provide an analysis that shows that every game should have some sections that are locally pathological, assuming that both players can potentially win the game. We also modify the minimax algorithm to recognize local pathologies in arbitrary games and cut off search accordingly (shallower search is more effective than deeper search when local pathologies occur). We show experimentally that our modified search procedure avoids local pathologies and consequently provides improved performance, in terms of decision accuracy, when compared with the minimax algorithm. In addition, we provide an experimental evaluation on the African game of Kalah, which shows the improved performances of our suggested error‐minimizing minimax algorithm when there is a large degree of pathology.     

Fretting damage assessment of titanium alloys using orientation imaging microscopy

The formation of fretting damage and cracks depends strongly on the microstructure. Recent advances in orientation imaging microscopy (OIM) make it possible to obtain new assessment measurements of the near-surface layers containing fretting damage. In particular, crystallographic grain orientation, misorientations between grains, accumulation of plastic deformation, and the evolution of microstructure leading to microtexture formation and twinning can be determined using OIM. Insight into the hexagonal close packed (HCP) structured metals and alloys is the focus of this study. The examination of the subsurface layers of Ti–6Al–4 V samples reveals that OIM using electron backscatter diffraction (EBSD) is a useful tool to quantify evolution of strain-induced microstructural changes due to deformation in the near-surface layers both in surface treatment processes and in fretting or sliding conditions. Fretting damage in a commercially pure titanium (CP Ti) and a near α Ti–5Al–2.5Sn is also assessed to further evaluate this new characterization method. This study summarizes what can be gained from OIM and the challenges associated with using the technique to characterize near surface microstructures.     

Miscible blends of biobased poly(lactide) with poly(methyl methacrylate): Effects of chopped glass fiber incorporation

Poly(lactide) (PLA) and poly(methyl methacrylate) (PMMA) are melt compounded with chopped glass fiber using laboratory scale twin‐screw extrusion. Physical properties are examined using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile testing, impact testing, X‐ray computed tomography (CT) scanning, and field emission scanning electron microscopy (FE‐SEM). Molecular weight is determined using gel permeation chromatography (GPC). Miscibility of the blends is implied by the presence of a single glass transition temperature and homogeneous morphology. PLA/PMMA blends tend to show positive deviations from a simple linear mixing rule in their mechanical properties (e.g., tensile toughness, modulus, and stress at break). The addition of 40 wt % glass fiber to the system dramatically increases physical properties. Across all blend compositions, the tensile modulus increases from roughly 3 GPa to roughly 10 GPa. Estimated heat distortion temperatures (HDTs) are also greatly enhanced; the pure PLA sample HDT increases from 75 °C to 135 °C. Fiber filled polymer blends represent a sustainable class of earth abundant materials which should prove useful across a range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44868.     

Oxygen scavenging polymer coating prepared by hydrophobic modification of glucose oxidase

Trace oxygen in packaged foods, beverages, and pharmaceuticals can promote a range of oxidative degradation reactions and support microbial growth, ultimately impacting product quality and shelf-life. Oxygen scavenging active packaging systems have therefore been explored to control headspace oxygen content. Herein, we report on a hydrophobic ion pairing method to render glucose oxidase hydrophobic, and thus soluble in organic solvents. Hydrophobic modified glucose oxidase was blended with ethylene vinyl acetate and cast on the interior of glass vials to demonstrate potential as a commercially translatable coating method for enzyme immobilization. The resulting oxygen scavenging polymer coatings were topographically uniform and presented 0.553 μg/cm² enzyme at the coating interface. The coatings effectively reduced headspace oxygen by 2% in a closed-vial system filled 50 vol% with citrate buffer, pH 3.5. Less than 25% protein migrated from the coating over an 8-week leaching study, with no detectable protein leached in the first 4 weeks. Hydrophobic ion pairing of glucose oxidase enabled a facile, high-throughput enzyme immobilization technique without use of complicated, time-consuming surface modification chemistries and reagents. Such oxygen scavenging polymer coatings can support controlling headspace oxygen in packaged goods, and thus retaining stability of oxygen-sensitive components such as colors, flavors, and nutrients.     

Probing the localized-to-delocalized transition

Detailed understanding of the transition between localized and delocalized behaviour in mixed valence compounds has been elusive as evidenced by many interpretations of the Creutz-Taube ion, [(NH3)5Ru(pz)Ru(NH3)5]5+. In a review in 2001, experimental protocols and a systematic model to probe this region were proposed and applied to examples in the literature. The model included: (i) multiple orbital interactions in ligand-bridged transition metal complexes, (ii) inclusion of spin-orbit coupling which, for dpi5-dpi6 complexes, leads to five low-energy bands, two from interconfigurational (dpi-->dpi) transitions at the dpi5 site and three from intervalence transfer transitions, (iii) differences in time scale between coupled vibrations and solvent modes which can result in solvent averaging with continued electronic asymmetry defining 'class II-III', an addition to the Robin-Day classification scheme, and (iv) delineation of coupled vibrations into barrier vibrations and 'spectator' vibrations. The latter provide direct insight into localization or delocalization and time scales for electron transfer. In this paper, the earlier model is applied to a series of mixed-valence molecules.     

RF Testing on a Mixed Signal Tester

In this paper, testing of radio frequency (RF) devices with mixed-signal testers is discussed. General purpose automatic test equipment (ATE) will be used. In this paper, a more universal test structure utilizing RF building blocks is proposed. A global positioning system (GPS) device is used as an example to illustrate how to develop the RF test plan with this usage. The test plan developed includes fast, cost-effective and dedicated circuitry.

3-D electrical impedance tomography for piecewise constant domains with known internal boundaries

Electrical impedance tomography (EIT) is a badly posed inverse problem, but can be stabilized if one assumes that the conductivity is piecewise constant, with a relatively small number of distinct regions, and that the region boundaries are known, for example from prior anatomical imaging. With this assumption, we introduce a three-dimensional (3-D) boundary element method (BEM) model for the forward EIT map from injected currents to measured voltages, and 3-D inverse solutions for both BEM and the finite element method (FEM) which explicitly take into account the parameterization implied by the known boundary locations. We develop expressions for the Jacobians for both methods, since they are nonlinear, to more rapidly solve the inverse problem. We show simulation results in a torso geometry with the heart and lungs as inhomogeneities. In a simulation study, we could reconstruct the conductive values of some internal organs of a human torso with more than 92% accuracy even with inaccurate internal boundary locations, a randomized rather than constant conductivity profile (with the standard deviation of the Gaussian-distributed conductivities set to 20% of their mean values), signal to measurement noise of 50 dB, and with different meshes used for the forward and inverse problems. BEM and FEM perform similarly, leading to the conclusion that the choice between them should be based on secondary considerations such as computational efficiency or the need to model conductivity anisotropies     

High-throughput fabrication of organic nanowire devices with preferential internal alignment and improved performance

We demonstrate that arrays of nanowires of conjugated polymers can be easily produced by a simple embossing protocol, compatible with very large scale integration technology. The embossing process is shown to have the supplementary virtue to increase the internal degree of order of the nanowires, significantly enhancing their performance. This is applied to the fabrication of nanowire-based devices consisting of a liquid crystalline light-emitting polymer, of a liquid crystalline semiconducting polymer, and of an amorphous conducting polymer, illustrating the versatility and wide applicability of the method.     

Alcohol effects on intentional behavior: Dissociating controlled and automatic influences.

This research examined the effect of alcohol on intentional behavior using a process dissociation procedure to separate the influences of conscious controlled processes from those of unconscious automatic processes. In 2 identical experiments, 24 male social drinkers studied a list of words before they received either 0.56 g/kg alcohol, an alcohol placebo, or soda. Participants then performed a word stem completion test that provided estimates of controlled influences and of automatic influences on their responses. The results of the 2 experiments were consistent. Comparisons among the treatments showed that alcohol reduced conscious controlled processes and left automatic processes unchanged. The findings contribute to understanding how the drug may reduce cognitive control of intentional behavior and raise important questions concerning personal and environmental factors that might mediate these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Indirect Cost Categorization and Allocation by Construction Contractors

In many instances, the architect∕engineer is responsible for the drafting of construction contracts. The importance of the drafter's clearly defining direct and indirect costs for contract items receiving cost reimbursement is reinforced by this survey of contractors. The survey asks contractors to classify a list of 44 items as their company would, with respect to project and home-office overhead and direct and indirect costs. The results of the survey indicate a lack of standard usage of these terms by industry. The survey also is used to investigate the manner in which contractors allocate home-office overhead to contracts.