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This work analyses the mutual dependence linking digital platforms, i.e., ‘Big Tech’, and the US military apparatus. Three main elements at the roots of such dependence are detected: an ‘originary linkage’ binding the development of digital platforms with governments’ military R&D efforts; the critical nature of infrastructures and technologies controlled by platforms; and their role as their government’s ‘eyes and ears’ (both at home and abroad). Focusing on the US, we first document the growing relevance of these corporations as US Department of Defense contractors. Second, we explore a selection of multi-year contracts entrusting platforms to develop and manage critical technologies and infrastructures for military purposes. Finally, we document the direct involvement of major US-based platforms in war scenarios. [ABSTRACT FROM AUTHOR]

In this paper, the structural, mechanical, electronic, and thermodynamic properties of Ir 3 TM (TM = Sc, Ti, and V) intermetallic compounds in the cubic (L1 2) and hexagonal (D0 19 and D0 24) phases are presented. The outcomes of the simulation rely on density functional theory (DFT) within the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) based on the full-potential linearized augmented plane wave (FP-LAPW) approach. The existing study was performed on the L1 2 cubic phase. in addition to hexagonal D0 24 and D0 19 phases, which may be relative but differ in the way that the atomic layers are stacked. The calculated total, cohesive energy, and heat formation suggest that the Ir 3 Sc compound can be stable in the D0 24 phase because of an overlap between the L1 2 and D0 24 phases with a total energy difference of around 0.026 eV/atom. Ir 3 Ti and Ir 3 V are more stable in L1 2 and D0 19 , respectively. From elastic constants calculations, it reveals that the studied compounds are mechanically stable and harder in the cubic phase than hexagonal phase. However, Ir 3 Sc has the lowest hardness due to its relative ductility. Inversely, Ir 3 V has the maximum hardness with a lack of ductility. It was observed that these compounds have an elastic anisotropy based on the three-dimensional Young's modulus surface, and Ir 3 Sc has the strongest anisotropy, while Ir 3 V has the weakest in the L1 2 phase. The total density of state (TDOS) calculations shows that Ir 3 Ti and Ir 3 V are stable in the L1 2 and D0 19 phases, respectively, except for the Ir3Sc compound which might undergo a martensitic transition. Also, the pseudogap for Ir 3 V moves quite close to the Fermi level, indicating that the covalent bonding in this compound is sharper than the other compounds. Moreover, via the quasi-harmonic Debye model within the Gibbs computational code, thermodynamic properties are calculated and analyzed with temperature and pressure. [ABSTRACT FROM AUTHOR]

L1 2 -precipitate-strengthened multi-component alloys (MCAs) possess exceptional combination of strength and ductility. However, the high production costs of L1 2 -containing MCAs impede their industrial application. This study introduces a novel approach for designing cost-effective L1 2 -containing MCAs by microalloying Al and Ti with a base composition of Fe 50 Ni 30 Cr 20 (at%). Three types of MCAs were investigated in this study: Fe 50.13 Ni 28.84 Cr 18.56 Al 1.39 Ti 1.08 (1Ti alloy), Fe 46.53 Ni 27.32 Cr 19.91 Al 3.44 Ti 2.80 (3Ti alloy), and Fe 48.51 Ni 25.93 Cr 15.75 Al 5.10 Ti 4.71 (5Ti alloy) (at%). An increase in the (Al, Ti) content from 1 to 3 at% accelerates the formation of L1 2 particles, whereas an increase in the (Al, Ti) content from 3 to 5 at% leads to the activation of the brittle B2 and D0 24 phases. The rapid co-precipitation of the L1 2 , B2, and D0 24 phases in the 5Ti alloys substantially hinders recrystallization during annealing, whereas the 3Ti alloys exhibit the highest rate of recrystallization upon annealing at 600 and 700 °C, mainly due to the reduction in the stacking fault energy of the matrix. The 5Ti alloys exhibit the highest hardness and the lowest plasticity owing to the presence of brittle B2 and D0 24 precipitates. By contrast, the 3Ti alloy annealed at 600 °C, in which dense and relatively fine L1 2 particles precipitated, exhibits a superior combination of hardness and plasticity. This study provides insights into the composition and annealing condition-dependent precipitation, recrystallization, and mechanical properties of ferrous MCAs. • Development of FeNiCr multi-component alloys containing L1 2 particles. • Composition and annealing condition-dependent precipitation, recrystallization behavior. • Fe 46.5 Ni 27.3 Cr 19.9 Al 3.4 Ti 2.8 (at%) exhibiting superior hardness and plasticity. [ABSTRACT FROM AUTHOR]

We present an interface-level first principles study on the formation of L1 2 -phase nano-structures in dilute Al-Zr-Y alloys. All energetics, relevant to bulk substitution, interface formation, interfacial coherent strain and segregation, were calculated and used to evaluate the nucleation and relative stabilities of various possible L1 2 nano-structures. The following new insights were obtained. Only matrix-dissolved solutes Y and Zr can strongly substitute the X sublattice sites in L1 2 -Al 3 X (X = Zr or Y), while the inter-substitution of Al 3 Zr(L1 2) and Al 3 Y(L1 2) is energetically forbidden. Solute Zr strongly segregate to the Al/Al 3 Y interface, in favor to develop a Zr-rich shell surrounding L1 2 -Al 3 Y. Further energetics analyses based on the classic homogeneous nucleation theory clarified the intricate correlation of the formation of complex L1 2 -phase nano-structures with the Zr/Y atom ratio and the aging temperature. Based on which, the experimental observed L1 2 -phase nano-structures in dilute Al-Zr-Y alloys were also explained. • First-principles calculations were performed to investigate the formation of various L1 2 -phases in dilute Al-Zr-Y alloys. • The nucleation energies of L1 2 -phases were correlated with the Zr/Y ratio and the aging temperature. • The core-shelled Al 3 Zr(Y) structure is more preferred at lower Zr/Y ratios and/or higher temperatures. [ABSTRACT FROM AUTHOR]

The lightweight Al 3 Ti intermetallic compound shows superior properties at elevated temperatures but its room-temperature brittleness largely limits its usefulness. We propose Al 3 Ti-based lightweight medium-entropy alloys (MEAs) with selected alloying elements, which change Al 3 Ti from a tetragonal D0 22 structure to a ductile cubic L1 2 one with embedded hard B2 and D8a phases. A combination of improved ductility and strength can be achieved. Four lightweight AlTiCrMnFeCu MEAs (ρ = 3.65∼4.27 g/cm3) with tunable balance between hardness and ductility were fabricated. Ti and Fe promoted the formation of hard B2 phase, while Cr and Mn favored the formation of D8a phase which strengthened the alloy at the minor expense of ductility. The compressive yield and peak strengths of the MEAs e.g., Al 55 Ti 20 Cr 5 Mn 10 Fe 5 Cu 5 , can reach as high as 650 MPa and 1366 MPa, respectively, with its fracture strain around 17 %. This study provides useful information for designing Al 3 Ti-based lightweight MEAs with desirable properties. [Display omitted] [ABSTRACT FROM AUTHOR]

We report the microstructures and mechanical properties of a novel Co-free Fe 46.0 Ni 28.6 Cr 18.5 Al 3.9 Ti 3.0 multicomponent alloy containing L1 2 particles with a high density and heterogeneous distribution. The sample annealed at 600 °C for 3 h exhibited various types of L1 2 particles such as continuous, discontinuous, and incoherent precipitates. The enhanced precipitation strengthening by the heterogeneous precipitation and activation of multiple strengthening mechanisms such as dislocation plasticity, multi-variant stacking faults, and deformation-induced 9R/D0 24 phases could lead to an exceptional combination of strength and ductility (ultimate tensile strength: 1465 MPa, yield strength: 1265 MPa, total elongation: 17%). [Display omitted] [ABSTRACT FROM AUTHOR]

Developing alloys with excellent strength-ductility combination is urged desirable for advanced structural application. However, it still remains challenging in spite of years' efforts. Face centered cubic (FCC) high-entropy alloys (HEAs) commonly exhibit superb ductility. However, the low strength and hardness would limit the development of the FCC-structured materials. Here, the FCC + L12 + BCC structured CoFeMnNiMo 0.2 Alx were designed and prepared. The CoFeMnNiMo 0.2 Al 0.5 HEA displays outstanding compressive properties, whose ultra-high compressive strength is 1900 MPa and the fracture strain is 39.6%. The nano-hardness of the CoFeMnNiMo 0.2 Al 0.5 HEA is nearly 8 GPa. Moreover, the relationship between phase evolution, mechanical property, strengthening mechanism, and Mo, Al concentration are systematically discussed. These findings will shed light on exploring novel HEA systems with high performance for future usage. • Novel CoFeMnNiMo 0.2 -based HEAs were designed. • Macro- and nano-mechanical behaviors were investigated. • Microstructural evolution and Strengthening mechanism was systematically discussed. • Using H/E and H 3 /E 2 parameters, wear resistance of the current system was evaluated. [ABSTRACT FROM AUTHOR]

The mechanical, electronic and thermodynamic properties of Pd3M (M = Sc, Y) compounds have been investigated using the Full Potential Linearized Augmented Plane Wave (FP-LAPW) formalism. The generalized gradient approximation (GGA) is used to treat the exchange–correlation terms. The calculated formation enthalpies and the cohesive energies reveal that the L12 structure is more stable than the D0 2 4 one. The obtained lattice parameters and bulk modulus calculations conform well to the available experimental and theoretical results. The elastic and mechanical properties are analyzed and results show that both compounds are ductile in nature. The Debye temperature and melting temperature are also estimated and are in a good agreement with experimental findings. The total and partial densities of states are determined for L12 and D0 2 4 structures. The density of states at the Fermi level, N ( E F ), indicates electronic stability for both compounds. The presence of the pseudo-gap near the Fermi level is suggestive of formation of directional covalent bonding. The number of bonding electrons per atom n b and the electronic specific heat coefficient γ are also determined. The quasi-harmonic Debye model has been used to explore the temperature and pressure effects on the thermodynamic properties for both compounds. [ABSTRACT FROM AUTHOR]

Abstract New aluminum alloys with improved durability and thermal resistance are desired to improve the performance of high-voltage power transmission lines. These improvements must not significantly reduce the electrical conductivity of the Al alloys currently used for this application to maintain current levels of power transmission efficiency. Precipitation-hardened binary Al-Zr alloys have been shown to have promising electrical conductivity and strength. However, there is room for improving the alloy strength, while maintaining a relatively high electrical conductivity by controlled additions of Zn. The objective of this study is to experimentally examine the addition of Zn to Al-Zr alloys with subsequent heat treatment to improve mechanical properties via controlled precipitation hardening. Vickers microhardness and conductivity measurements, tensile test, scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, and selected area electron diffraction are used to measure the properties and determine the microstructure of Al-Zr-Zn alloys for a wide range of aging conditions. As expected, the results indicate that Al-Zr-Zn alloys have improved mechanical properties and slightly reduced electrical conductivity relative to Al alloys currently used for power transmission. However, it is determined that the addition of Zn is unable to improve the heat resistance of Al-Zr alloys. Highlights • New Al-Zr-Zn alloys are developed. • The alloys are compared to current Al alloys used for high-voltage power cables. • New alloys have improved mechanical properties. • New alloys have electrical conductivities that are nearly the same. • The addition of Zn to Al-Zr alloys is unable to improve the heat resistance. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (S. aureus; MRSA) is one of the most common bacterial pathogens and MRSA infections are characterized by high mortality rates. Antimicrobial peptides are considered one of the most promising drugs for the treatment of resistant strains of S. aureus. The present study aimed to examine the antimicrobial activity of L12 against numerous bacterial species using the broth microdilution method. Furthermore, the synergistic effect of L12 combined with various antibacterial drugs was tested, and its antibacterial mechanism was investigated by a checkerboard assay. The alterations in bacterial morphology were detected by electron microscopy, and biofilm formation and removal were tested by crystal violet staining. The present results suggested that L12 affected the growth of gram-positive strains, particularly S. aureus. Electron microscopy analysis suggested that L12 may target the cell membrane, and L12 increased the antibacterial activity of vancomycin and levofloxacin, exerting a synergistic effect. However, the minimal inhibitory concentrations (MICs) of L12 were not correlated with antibiotic resistance, the strains resistant to more antibiotics were not more resistant to L12. A sub-MIC of L12 was able to inhibit biofilm formation in a dose-dependent manner; however, concentrations of L12 ≤10 times the MIC were not sufficient to degrade previously formed biofilm. Collectively, the present study suggested that L12 may represent a novel potential therapeutic molecule for the treatment of S. aureus infections. [ABSTRACT FROM AUTHOR]

This paper investigates the consumption tax and subsidy as an environmental policy instrument for environmentally aware consumers by applying the model of price discrimination. We discover that a higher rate of subsidy should be set for less eco-friendly consumers for the purpose of achieving socially optimal environmental qualities under positive externalities and this retrogressive subsidization differs from the current progressive subsidization in the Japanese automobile industry, and could alleviate crowding out effects on prosocial behavior. Moreover, it is revealed that the optimal policy instrument for eco-friendlier consumers shifts from a subsidy to a tax, as the level of negative externalities increases. [ABSTRACT FROM AUTHOR]

This paper provides a general characterization of subgame-perfect equilibria for strategic timing problems, where two firms have the (real) option to make an irreversible investment. Profit streams are uncertain and depend on the market structure. The analysis is based directly on the inherent economic structure of the model. In particular, determining equilibria with preemptive investment is reduced to solving a single class of constrained optimal stopping problems. Further tools are derived for analyzing Markovian state-space models. Applications to typical models from the literature complete commonly insufficient equilibrium arguments, show when uncertainty leads to qualitatively different behavior, and establish additional equilibria that are Pareto improvements. [ABSTRACT FROM AUTHOR]

A non-cooperative solution, the Equilibrium in Secure Strategies (EinSS), is defined as an extension of the Nash equilibrium in pure strategies, and is meant to solve games where players are “cautious,” i.e. , looking for secure positions and avoiding threats. This concept abstracts and unifies ad hoc solutions already formulated in various applied economic games that have been discussed extensively in the literature. A general existence theorem is provided and then applied to the price-setting game in the Hotelling location model, to Tullock's rent-seeking contests, and to Bertrand–Edgeworth duopoly. Finally, competition in the insurance market game is re-examined and the Rothschild–Stiglitz–Wilson contract is shown to be an EinSS even when the Nash equilibrium breaks down. [ABSTRACT FROM AUTHOR]

The ab-initio calculations based on the density functional theory (DFT) have been performed to study the structural, mechanical, electronic, thermal and thermodynamic properties of Al3Sc and Al3Ti binary compounds and their ternary mixture Al3(Sc1−xTix) in L12 and D022 structures. The total energy calculations show that the L12 structure is the more stable one. The Al3Sc0.25Ti0.75 undergoes a martensitic transformation and the formation enthalpies and the lattice parameters decrease with increasing concentration x. The elastic constants are determined and the results show that all compounds are mechanically stable and the cubic cells are more easily deformed by shearing than by unidirectional compression. The elastic modulus indicates that the addition of Ti atoms to Al3Sc improves its ductility. The densities of states (DOSs) calculations show the strong spd hybridization which leads to the formation of a pseudo-gap near the Fermi level in ternary alloys. The densities of states at the Fermi level N(EF) confirm the phase stability. The quasi-harmonic Debye model is used to predict the thermal properties such as heat capacity, Debye temperature, Grüneisen parameter and thermal expansion coefficient of the considered alloys. The determination of Gibbs free mixing energy at different concentrations has been used to calculate the T–x diagram. [ABSTRACT FROM AUTHOR]

This paper investigates the industrial organization of the international drug trade. From the mid 1970s through the early 2000s, a few large-scale and hierarchically organized cartels dominated the market. Since 2006, dozens of smaller and more-specialized units have emerged. We notice that the prohibition efforts of federal governments (primarily Mexico and the U.S.) imposed costs asymmetrically across differently sized drug trafficking organizations (DTOs). Under president Calderon (office held from 2006–2012), efforts were arranged as “kingpin” or “decapitation” strategies and were primarily focused on arresting key leaders of the largest and most infamous operations. This asymmetric enforcement structure evoked unique strategic responses from differently sized DTOs. Larger DTOs splintered into smaller units. Smaller outfits remained small and sought more specialized roles in the more decentralized and competitive supply chain. Furthermore, we argue that subsequent changes in operating costs amidst this less concentrated environment, tended to exaggerate the asymmetric cost structure across differently sized DTOs. Larger DTOs in a more competitive illicit market cannot exploit economies of scale to maintain internal coordination and loyalty as easily as they once could with fewer rival DTOs. In result, the seemingly persistent industrial organization of the international drug trade has remained less concentrated than in previous decades. [ABSTRACT FROM AUTHOR]

A legacy of the pre-Great Depression period was the development of new copper capacity outside the USA. In order to avoid the utilization of this excess capacity in a competitive and possibly pyrrhic way, on March 28, 1935, the International Copper Cartel was formed. While production of cartel members was limited by the use of quotas in times of lower demand, during booms, the cartel removed all quotas in order to restrict the entry of the competitive fringe into the industry. In fact, many authors have considered the latter as a return to non-cooperative conduct. An alternative view, introduced by Montero and Guzmán (J Ind Econ 58(1):106-126, 2010), is that cooperation among members in booms could have been related to output-expanding strategies with the purpose of restricting entry of the competitive fringe in the industry through their own output expansion.In this paper, a theoretical model is developed in order to differentiate between cartel behavior in the presence of a competitive fringe during booms when firms are not cooperating. It shows that the price elasticity of the cartel supply should be smaller in booms than during recessions, when a non-cooperative behavior is considered in booms, while this may or may not be the case if firms continue cooperating—through an output-expanding cooperation—during booms. The price elasticity of the International Copper Cartel supply is then estimated using an econometric model, and found to be significantly larger in booms than in recessions. This supports the conclusion that members of the cartel cooperated during both booms and recessions. This finding raises the possibility that the International Copper Cartel of 1935-1939 actually could have enhanced social welfare by reducing price volatility, while also having little effect on the secular level of prices. [ABSTRACT FROM AUTHOR]

Agricultural pollution is extremely serious in China, and agricultural output quantity subsidy makes it even worse. This paper captures the impacts of agricultural subsidy, including quantity subsidy and innovation subsidy, on agricultural pollution. Agriculture output quantity, total pollution or emission, equilibrium price, consumer and producer surplus, government budget, and social welfare are all addressed in this study. The results show that emission-reducing innovation subsidy is better than quantity subsidy because it reduces the pollution from agriculture and profits for the agricultural firm are higher under innovation subsidy than under quantity subsidy. More importantly, output quantity and consumer surplus under innovation subsidy are also larger than those under quantity subsidy if the subsidy rate is not too high. This study finds that the importance of the environment to the consumer, marginal emission, and pollution tax will decrease output quantity, consumer and producer surplus and social welfare; however, agricultural subsidy increases them. Furthermore, this study indicates that innovation subsidy can alleviate the “food quantity safety and quality of environment” dilemma in agriculture. [ABSTRACT FROM AUTHOR]

This paper considers all-pay contests in which the relationship between bids and allocations reflects a small amount of noise. Prior work had focused on one particular equilibrium. However, there may be other equilibria. To address this issue, we introduce a new and intuitive measure for the proximity to the all-pay auction. This allows, in particular, to provide simple conditions under which actually any equilibrium of the contest is both payoff equivalent and revenue equivalent to the unique equilibrium of the corresponding all-pay auction. The results are shown to have powerful implications for monopoly licensing, political lobbying, electoral competition, optimally biased contests, the empirical analysis of rent-seeking, and dynamic contests. [ABSTRACT FROM AUTHOR]

When a new product or technology is introduced, potential consumers can learn its quality by trying it, at a risk, or by letting others try it and free-riding on the information that they generate. We propose a dynamic game to study the adoption of technologies of uncertain value, when agents are connected by a network and a monopolist seller chooses a profit-maximizing policy. Consumers with low degree (few friends) have incentives to adopt early, while consumers with high degree have incentives to free ride. The seller can induce high-degree consumers to adopt early by offering referral incentives – rewards to early adopters whose friends buy in the second period. Referral incentives thus lead to a ‘double-threshold strategy’ by which low and high-degree agents adopt the product early while middle-degree agents wait. We show that referral incentives are optimal on certain networks while inter-temporal price discrimination is optimal on others. [ABSTRACT FROM AUTHOR]

We show that if a firm can subcontract production to an informal sector, an increase in union power may either increase or decrease innovation. An increase in union power makes the firm worse off irrespective of its effect on innovation. However, in contrast to the usual belief, an increase in union power may increase consumer surplus and decrease union utility by affecting innovation, thus suggesting that a union may not want to be too powerful. An increase in union power may create an ambiguous effect on social welfare. Our analysis provides new insights to the relation between union power and innovation. [ABSTRACT FROM AUTHOR]

I present a model of dynamic pricing and diffusion of a network good sold by a monopolist. In the model, the network good is a subscription social network good . This means that in each period, each consumer has to pay a subscription price to use the good, and the utility derived from subscribing to the good increases as more of her neighboring consumers subscribe. Consumers myopically optimize their subscription decisions, and the monopolist chooses a sequence of subscription prices that maximizes his discounted sum of per-period profits. Three main results emerge. First, I characterize a unique steady state of the monopoly market. Second, I find that optimal sequences of subscription prices oscillate around the subscription price at the steady state. Third, I analyze how changes in the monopolist's discount factor and the density of the social network affect the subscription price, subscription rate, and deadweight loss at the steady state. [ABSTRACT FROM AUTHOR]

Laser powder-bed fusion was used to create an Al-7Ce-10Mg-0.71Zr-0.23Sc (wt.%) alloy, using hypoeutectic Al-7Ce-10Mg (wt.%) pre-alloyed powder blended with either elemental Zr and Sc powders (∼20 µm in size), or pre-alloyed, concentrated Al-10Zr and Al-10Sc (wt.%) powders (comprised of 1-5 µm Al 3 Zr or Al 3 Sc particles embedded in a <45 μm Al-rich matrix). The effects of process parameters and powder selection on the homogeneity of the as-fabricated microstructure were investigated via metallography and compared to predictions from a simple numerical model describing the dissolution of Zr powders in the melt pool during printing. Both experiments and model show that decreasing scan speed leads to greater dissolution of Zr and Sc, but remelting has no significant effect. The samples produced with Al-10Zr and Al-10Sc powder additions show greater amounts of Zr and Sc dissolution than those produced with elemental Zr and Sc additions, because of the smaller size (5 µm for prealloyed vs. 20 µm for elemental) and lower melting point (1580 and 1320°C for Al 3 Zr, Al 3 Sc vs. 1850 and 1541°C for Zr, Sc) of the dissolving species. The alloys fabricated with prealloyed powders display larger amounts of very fine grains (1-2 µm) nucleated by primary L1 2 Al 3 (Zr,Sc) precipitates, and a clear hardening response during aging, consistent with supersaturated Zr and Sc forming a high number density of secondary L1 2 Al 3 (Zr,Sc) nanoprecipitates. [Display omitted] [ABSTRACT FROM AUTHOR]

This study examines the precipitation of AlCu solute clusters by re-aging at high temperatures for a long time. It provides evidence for their long-term stable existence in the range of 25–450 °C. In this study, T6 heat-treated Al–4Cu alloys were aged at 350 and 420 °C for 100 h, respectively. The microstructure characteristics of the alloys, corresponding to three kinds of treatments were examined using scanning electron microscopy, high-resolution transmission electron microscopy, and high-resolution scanning transmission electron microscopy. Two types of AlCu solute atomic clusters precipitate during the two re-aging processes. One is disordered clusters precipitated by aging at 350 °C for 100 h, and the other is L1 2 ordered clusters precipitated by aging at 420 °C for 100 h. Face centered cubic (Al)+L1 2 (AlCu cluster) microstructure was successfully prepared by re-aging at 420 °C for 100 h. Owing to this microstructure, the tensile strength and yield strength of the re-aged alloy at 420 °C was higher than that of the re-aged alloy at 350 °C. The structure and composition of the L1 2 AlCu solute clusters were studied using transmission electron microscopy and its energy-dispersive X-ray spectrometry. The atoms belonging to the cluster mostly adapt to the Al lattice positions, and few atoms are located in the interstitial position of FCC Al. In this study, utilizing AlCu solute clusters is proposed as a novel and promising approach for designing heat-resistant Al–Cu system alloys. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of two die-cast hypoeutectic Al-Ce-based alloys modified with Sc, Zr and Er micro-additions – Al-1.5Ce-0.14Sc-0.03Zr with high Sc content and Al-1.4Ce-0.02Sc-0.06Zr-0.003Er (at%) with low Sc content – are studied, with focus on the two strengthening phases: micron-scale Al 11 Ce 3 platelets formed on solidification and L1 2 Al 3 (Sc,Zr,Er) nanoprecipitates formed during aging. The evolution of microstructure and microhardness upon isothermal aging at 350 and 400 °C, and the creep resistance at 300 °C, are studied and compared to alloys containing only one of these strengthening phases. The Al 11 Ce 3 and L1 2 phases form mostly independently of each other, except in the low-Sc alloy where scavenging of Er and Si by Al 11 Ce 3 on solidification reduces the kinetics of precipitation and number density of the L1 2 precipitates formed on subsequent aging. The two strengthening phases, while mostly independent of each other chemically, interact synergistically in terms of strengthening. At ambient temperature, the hardness of the Al 11 Ce 3 - and L1 2 -strengthened alloys is higher than that of similar alloys containing only one strengthening phase. At 300 °C, the creep strain rate is reduced by as much as five orders of magnitude in the Al 11 Ce 3 - and L1 2 -strengthened alloys compared to alloys containing only L1 2 precipitates. This improvement in both room and elevated-temperature mechanical properties is modeled through a combination of load transfer from the Al 11 Ce 3 micro-platelets, and precipitation strengthening from the Al 3 (Sc,Zr,Er) nanoprecipitates. [Display omitted] [ABSTRACT FROM AUTHOR]

Many firms offer “core” and “side” goods in the sense that side-good consumption is conditional on core-good consumption. Airports are a common example where the supply of runway and terminal capacity is the core good and the supply of various concession services (for example, car rental services) is the side good. While side-good supply can be responsible for a major share in total revenue, monopoly regulation typically concentrates on the control of core-good prices (“core prices” in short). Whether market power can indeed be effectively controlled by the regulation of core prices alone then depends on whether core-good consumption is a function of the price for side goods. This study empirically shows that a one-dollar increase in the daily car rental price reduces passenger demand at 199 US airports by more than 0.36%. A major implication of our findings is that for the case of airports, the effective control of market power may require regulation of both prices for core and side goods. [ABSTRACT FROM AUTHOR]

NGOs compete in mission statements. Opportunities for impact vary across issues—NGOs with broader missions expect to execute higher-impact projects but provide less precision to donors as to the sorts of projects that will be funded. This matters if donors have preferences amongst issues. The mission-design problem faced by an impact-motivated NGO is analyzed. Interestingly, expected donations are non-monotonic in mission-width. A monopoly NGO engages in “donor-stretching,” choosing a mission statement that includes issues not preferred by any of its donors, but still narrower than socially desirable. Under free entry, issue-widths are strategic complements amongst NGOs. In equilibrium there are too many NGOs, each with too narrow a mission. The issue-space is exactly donor-covered (all donors will have an NGO they wish to give to) but issue over-covered (mission statements overlap). Expected NGO impact is higher for issues at the periphery of any particular NGO's issue-domain, which is socially inefficient. [ABSTRACT FROM AUTHOR]

We analyze the manner in which a monopolist designs its product line when facing customers with limited attention. We assume that consumers simplify complex problems by neglecting some relevant aspects. This creates an incentive for a firm to supply simple products. Simultaneously, limited attention offers partial protection to customers from the monopolist's market power. We further assume that customers’ attention varies with the set of alternatives. A firm may then manipulate its customers’ attention through the range of products it offers. We show that a firm can increase its profit by introducing goods that have the sole function of manipulating consumer attention. Finally, we analyze the impact of limited attention on the screening of heterogeneous customers. [ABSTRACT FROM AUTHOR]

Professional sports teams receive large subsidies, some in excess of $500 million, from local governments for the construction of new facilities. These subsidies cannot be explained by tangible economic benefits, and estimates of the value of intangible benefits also fall short of typical subsidies. In this paper, we incorporate fans’ reference-dependent preferences into a model of the bargaining between local governments and teams. The model predicts that teams use relocation threats to exploit fans’ utility loss from team departures, a negative deviation from the status quo, to extract large subsidies from local governments. Fans’ loss aversion provides an explanation of the current team distribution, and observed team relocation and league expansion decisions in North America. The model also highlights the importance of anti-trust exemptions of the leagues in creating credible relocation threats for existing teams. [ABSTRACT FROM AUTHOR]

We consider welfare effects of parallel imports under a possibility of piracy, by constructing a model where a monopoly firm sells its product in a developed country and in a developing country. We show that parallel imports do not always make the firm worse off and consumers better off. Sometimes parallel imports benefit both the firm and consumers, irrespective of the existence of piracy. However, piracy makes parallel imports more preferable to consumers and less preferable to the firm. We also suggest that a developing country’s policy on piracy can be internationally coordinated with a developed country's policy on parallel imports, so as to improve the welfare of these countries. [ABSTRACT FROM AUTHOR]

This paper provides a unifying framework to analyze whether a monopoly transit provider will under or over-supply frequency. To this end we couch the problem in term of Spence [(1975). Monopoly, quality and regulation.The Bell Journal of Economics, 6,417–429] who analyzed the incentives to provide quality by a monopolist. We show that all of the results of a recent academic exchange discussing this topic are special cases of Spence [(1975). Monopoly, quality and regulation.The Bell Journal of Economics, 6,417–429], albeit with an adjustment in order to take into account the cost structure of frequency provision in the case of public transport. In theory then, there are cases when a monopolist may offer optimal or above optimal levels of frequency without requiring subsidies. However, public transport is rarely provided by an unregulated monopolist. Rather, these services are usually provided either by an exclusive operator under regulated fares or by a group of competing operators, with or without fare regulation. We show that in the first case frequency will always be below the social optimal level. [ABSTRACT FROM PUBLISHER]

This paper shows how a multimarket incumbent can use low pre-entry prices for entry deterrence. We consider an incumbent who operates in two independent markets and has private information about his production cost. In one of the markets, there is a potential entrant offering a differentiated product. The most reasonable perfect Bayesian equilibrium is either the least-cost separating equilibrium or the pooling equilibrium where both types of incumbents set the low-cost monopoly prices. This equilibrium may involve a downward distortion in the pre-entry prices of both markets. Our model has interesting implications for antitrust regulation as well as for international trade policy. First, predatory tests based on a single market are inadequate for a multimarket incumbent. Second, a lower price in a foreign market is neither a necessary nor a sufficient condition for the existence of entry deterrence in a foreign market. [ABSTRACT FROM AUTHOR]

Abstract: An Al–6.3Li–0.07Sc–0.02Yb (at.%) alloy is subjected to a double-aging treatment to create nanoscale precipitates, which are studied by atom-probe tomography and transmission electron microscopy. After homogenization and quenching, Yb atoms form clusters exhibiting L12-like order. A first aging step at 325°C leads to a doubling of microhardness as a result of the formation of coherent precipitates with an Al3Yb-rich core and an Al3Sc-rich shell. The core and shell both exhibit the L12 structure and both contain a large concentration of Li, which substitutes for up to 50% of the Sc or Yb atoms at their sublattice positions. These core/single-shell precipitates provide excellent resistance to overaging at 325°C. Subsequent aging at 170°C increases the microhardness by an additional 30%, through precipitation of a metastable δ′-Al3Li second shell on the core/single-shell precipitates, thereby forming a chemically and structurally complex core/double-shell structure. The metastable δ′-Al3Li phase is observed to form exclusively on pre-existing core/shell precipitates. [Copyright &y& Elsevier]

Abstract: Ribosomal “stalk” protein L12 is known to activate translational GTPases EF-G and EF-Tu, but not much is known about its role in relation to other two translational G factors, IF2 and RF3. Here, we have clarified the role of L12 in IF2-mediated initiation of bacterial protein synthesis. With fast kinetics measurements, we have compared L12-depleted 50S subunits with the native ones in subunit association, GTP hydrolysis, Pi (inorganic phosphate) release and IF2 release assays. L12 depletion from 50S subunit slows the subunit association step significantly (∼40 fold) only when IF2·GTP is present on the 30S preinitiation complex. This demonstrates that rapid subunit association depends on a specific interaction between the L12 stalk on the 50S subunit and IF2·GTP on the 30S subunit. L12 depletion, however, did not affect the individual rates of the subsequent steps including GTP hydrolysis on IF2 and Pi release. Thus, L12 is not a GTPase activating protein (GAP) for IF2 unlike as suggested for EF-G and EF-Tu. [Copyright &y& Elsevier]

Abstract: The addition of Ti to a γ′-strengthened Ni-base model alloy shows a strong preference of Ti for the γ′-phase. Ti strongly influences the diffusion behaviour of constituents of the Ni3Al (γ′) phase, although the mechanism is uncertain. Electron energy loss channelling experiments were therefore performed to determine the electronic structure in the vicinity of the Ti atom. The experimental results showed an increase in the Ti L3/L2 ratio when probing the Ni sublattice planes compared to the Al sublattice planes, indicating a strong charge transfer from the Ti to the Ni atoms. This finding was supported by first-principles calculations, indicating an increase in electron density in the vicinity of the Ti atom and a strengthening of the chemical bonds. [Copyright &y& Elsevier]

A well characterized, peptide derivative of bovine lactoferrin, L12, has been shown to possess anticancer properties in multiple cell lines. However, adverse side effects in normal tissues and poor plasma kinetics that hinder the clinical effectiveness of current chemotherapeutics also deter the potential for effective delivery of this L12 peptide. To overcome these limitations, we have developed an Elastin-like polypeptide (ELP) carrier that has the potential to thermally target therapeutic peptides and chemotherapeutics to a tumor site. The coding sequence of ELP was modified with the L12 peptide at the C-terminus and a membrane transduction domain derived from the HIV- 1 Tat protein at the N-terminus (Tat-ELP-L12). The thermally responsive Tat-ELP1-L12 is soluble in aqueous solutions at 37°C but aggregates near 41°C, which makes Tat-ELP1- L12 ideal for targeting to solid tumors on application of focused hyperthermia. We observed that under hyperthermia conditions at 42°C, Tat-ELP1-L12 mediated cytotoxicity in MIA PaCa-2 pancreatic adenocarcinoma cells was enhanced by nearly thirty-fold. We investigated the mechanisms of cell death and found evidence of mitochondrial membrane depolarization and caspase activation, which are characteristic of apoptosis, as well as, increased membrane permeability, as shown by LDH release. These results suggest that Tat-ELP1-L12 possesses cytotoxic properties to cancer cells in vitro and may have the potential to provide an effective vehicle to thermally target solid tumors. [ABSTRACT FROM AUTHOR]

Ternary interdiffusion in L12-Ni3Al with ternary alloying addition of Re was investigated at 1473 K using solid-to-solid diffusion couples. Interdiffusion flux of Ni, Al, and Re were directly calculated from experimental concentration profiles and integrated for the determination of average ternary interdiffusion coefficients. The magnitude of main interdiffusion coefficients $$ \bar{\tilde{D}}_{\text{NiNi}}^{\text{Al}} $$ and $$ \bar{\tilde{D}}_{\text{AlAl}}^{\text{Ni}} $$ was determined to be much larger than that of the main interdiffusion coefficient $$ \bar{\tilde{D}}_{\text{ReRe}}^{\text{Al (or Ni)}}. $$ A moderate tendency for Re to substitute for Al sites was reflected by its influence on interdiffusion of Al, quantified by large and positive $$ \bar{\tilde{D}}_{\text{AlRe}}^{\text{Ni}} $$ coefficients. Similar trends were observed from ternary interdiffusion coefficients determined by Boltzmann-Matano analysis. Profiles of concentrations and interdiffusion fluxes were also examined to estimate binary interdiffusion coefficients in Ni3Al, and tracer diffusion coefficients of Re (5.4 × 10−16 ± 2.3 × 10−16 m2/s) in Ni3Al. [ABSTRACT FROM AUTHOR]

Abstract: The additions of alloying elements to Ni- and Pt-base alloys influence the microstructure and thereby the creep properties, whereas the mechanism is uncertain. Therefore atomic site location by channelling enhanced microanalysis (ALCHEMI) was used to determine the site partitioning of ternary and quaternary alloying elements in the L12-ordered γ′-phase. Two ternary Ni–Al alloys with Cr and Ti additions were investigated. The measured site partitioning showed that Cr and Ti atoms prefer the Al-sublattice sites. For a ternary Pt–Al–Cr alloy, it was found that Cr atoms occupy Al sites. The influence of Ni as a fourth alloying element in a Pt–Al–Cr–Ni alloy on the site partitioning was also investigated. The detected results give evidence that in the quaternary alloy Cr and Ni atoms prefer the Pt sublattice. First principles calculations were used to support the experimental data. [Copyright &y& Elsevier]

Abstract: Efficient protein synthesis in bacteria requires initiation factor 2 (IF2), elongation factors Tu (EF-Tu) and G (EF-G), and release factor 3 (RF3), each of which catalyzes a major step of translation in a GTP-dependent fashion. Previous reports have suggested that recruitment of factors to the ribosome and subsequent GTP hydrolysis involve the dimeric protein L12, which forms a flexible “stalk” on the ribosome. Using heteronuclear NMR spectroscopy we demonstrate that L12 binds directly to the factors IF2, EF-Tu, EF-G, and RF3 from Escherichia coli, and map the region of L12 involved in these interactions. Factor-dependent chemical shift changes show that all four factors bind to the same region of the C-terminal domain of L12. This region includes three strictly conserved residues, K70, L80, and E82, and a set of highly conserved residues, including V66, A67, V68 and G79. Upon factor binding, all NMR signals from the C-terminal domain become broadened beyond detection, while those from the N-terminal domain are virtually unaffected, implying that the C-terminal domain binds to the factor, while the N-terminal domain dimer retains its rotational freedom mediated by the flexible hinge between the two domains. Factor-dependent variations in linewidths further reveal that L12 binds to each factor with a dissociation constant in the millimolar range in solution. These results indicate that the L12-factor complexes will be highly populated on the ribosome, because of the high local concentration of ribosome-bound factor with respect to L12. [Copyright &y& Elsevier]

Abstract: The mechanical data of novel alloys based on the pseudo-ternary system Ni3Al–Ni3Ti–Ni3V was assessed. This alloy system exhibits dual multi-phase microstructures and was described in part I of this paper [Acta Mater 2005:53]. The mechanical characterization was performed on as-cast and hot-worked material. The new alloys show extremely high yield stresses with good temperature retention, when compared with conventional nickel-based alloys. Over a broad temperature range fracture preferentially occurred along grain boundaries. The compressive creep test conducted at temperatures between 1150 and 1250K showed the presence of threshold stress and also extremely low creep rates when compared with the conventional Ni-based superalloys with dispersed oxide particles. The obtained results are promising for the development of a new type of high-temperature structural material. [Copyright &y& Elsevier]

Abstract: The constitution and microstructure of intermetallic alloys based on the Ni3Al–Ni3Ti–Ni3V pseudo-ternary system and composed of the phases L12, DO22 and DO24 were investigated. Particular emphasis is paid to alloys with a relatively low Ti content. High-temperature annealing of these alloys leads to the formation of a two-phase microstructure at the micron-scale, which consists of the phases L12 +A1. This microstructure can additionally be refined by a decomposition reaction occurring upon annealing below the eutectoid temperature, according to which the Al phase is transformed into the L12 +DO22 phases. In this way, a novel microstructure is formed at the sub-micron scale. The dual multi-phase intermetallic alloys exhibit highly coherent interface structures between the constituent phases of L12 and D022 not only at a micron scale but also at a sub-micron scale and also display high microstructural stability at high temperature. [Copyright &y& Elsevier]

This work studies the impact of adding 0.5 wt.% Si on the formation of Al 3 (Sc,Zr) L1 2 precipitates in a lean Al-Sc-Zr alloy. Precipitation kinetics are significantly accelerated when ageing at 300 and 375 °C in the presence of Si. At 375 °C, peak hardness occurs in a few minutes and is maintained up to 200 h at 375 °C. High resolution TEM reveals the presence of very fine core-shell L1 2 dispersoids ~5 nm in size that remain stable for up to 200 h at 375 °C. Using high-resolution energy dispersive X-ray spectroscopy (EDX) and atom probe tomography (APT), the presence of Si and Fe is detected in the core of the dispersoids, where their content decreases as a function of ageing time. Similar Si and Fe compositions were observed inside the dispersoids for both alloys regardless of bulk Si content. Both Si and Fe are found to have preference for the Al site in the L1 2 structure, which is supported by density functional theory (DFT) calculations. DFT also explains the decrease of Si and Fe over time, showing that there is no thermodynamic driving force for either Si or Fe to be present in the L1 2. Instead Si and Fe are found to play a crucial role at the early stages of clustering, but are expelled from the particles when they stabilise into L1 2 structures. [Display omitted] [ABSTRACT FROM AUTHOR]

The full potential linearized augmented plane wave (FP-LAPW) method was used to investigate the ground states as well as the mechanical, electronic, magnetic and optical properties of M 3 V (M: Pd, Pt) compounds. The generalized gradient approximation (GGA) of Perdew-Burke and Ernzerhof (PBE-GGA) is employed to treat the exchange-correlation potential for all the calculations except for structural properties where both Wu and Cohen generalized gradient approximation (WC-GGA) and Perdew and Wang local spin density approximation (LSDA) have been added. The cohesive energies, the formation enthalpies and the densities of states at the Fermi level N(E F) show that the D0 22 structure is more stable than D0 23 and L1 2. The lattice parameter and bulk modulus results agree well with the available experimental measurements and theoretical predictions. The elastic and mechanical properties are predicted and show that both compounds exhibit ductile behavior. Furthermore, our calculations of Debye and melting temperatures are in good agreements with experimental results reported in the literature. The densities of states (DOS) show that strong d-d hybridization is behind the formation of the pseudogap at the Fermi level. The contours of the valence charge densities show combinations of metallic and covalent bonds. The number of bonding electrons per atom n b , the electronic specific heat coefficient γ, and the electron-phonon coupling constant λ, are determined. The obtained values of the magnetic moments and polarization coincide with the reported values for both D0 22 and L1 2 structures. Moreover, the optical properties, including the dielectric functions, extinction coefficient K (ω), reflectivity coefficient R (ω) and energy loss function L (ω) are studied in the range of 0–14 eV. Image 1 • The formation enthalpy and cohesive energy are calculated in nonmagnetic (NM) and magnetic (FM) states. • The ground states properties are studied in the L1 2 , D0 22 and D0 23 structures, using GGA, WC-GGA and LDA approximations. • The elastic and mechanical properties are predicted for both compounds. • The contours of the valence charge density are plotted in different atomic plans. • The optical properties are studied as well in the range 0–14 eV, for both compounds. [ABSTRACT FROM AUTHOR]

The Co–V system has been reviewed. Density functional theory (DFT) calculations using the generalized gradient approximation (GGA) were used to obtain the energies for the end-members for all three intermediate phases, Co 3 V, σ and CoV 3. Results from DFT calculations considering spin polarization were used to evaluate the CALPHAD (Calculation of phase diagrams) model parameters. The method to evaluate the contribution of the magnetism to the energies of Co-rich compounds that was introduced in our previous work is presented in more detail in the present work. For the description of the σ phase, the magnetic part of the total energy is included in the description of the pure Co end-member compound resulting in a non-linear description of the magnetic contribution over composition. The calculated phase diagram obtained from the present CALPHAD description is in good agreement with the experimental data. The metastable FCC-L1 2 phase diagram was calculated and compared with experimental data. [ABSTRACT FROM AUTHOR]