Chalcogenides such as CdTe, Cu(In,Ga)(S,Se)2 (CIGSSe), and Cu2ZnSn(S,Se)4 (CZTSSe) have enabled remarkable advances in thin-film photovoltaic performance, but concerns remain regarding (i) the ...toxicity (CdTe) and (ii) scarcity (CIGSSe/CdTe) of the constituent elements and (iii) the unavoidable antisite disordering that limits further efficiency improvement (CZTSSe). In this work, we show that a different materials class, the BaCu2SnSe x S4–x (BCTSSe) system, offers a prospective path to circumvent difficulties (i–iii) and to target new environmentally friendly and earth-abundant absorbers. Antisite disordering and associated band tailing are discouraged in BCTSSe due to the distinct coordination environment of the large Ba2+ cation. Indeed, an abrupt absorption edge and sharp associated photoluminescence emission demonstrate a reduced impact of band tailing in BCTSSe relative to CZTSSe. Our combined experimental and computational studies of BCTSSe reveal that the compositions 0 ≤ x ≤ 4 exhibit a tunable nearly direct or direct bandgap in the 1.6–2 eV range, spanning relevant values for single- or multiple-junction photovoltaic applications. For the first time, a prototype BaCu2SnS4-based thin-film solar cell has been successfully demonstrated, yielding a power conversion efficiency of 1.6% (0.42 cm2 total area). The systematic experimental and theoretical investigations, combined with proof-of-principle device results, suggest promise for BaCu2SnSe x S4–x as a thin-film solar cell absorber.
The high entropy alloy containing refractory metals Mo-Nb-Ta-W has a body-centered cubic structure, which is not surprising given the complete mutual solubility in BCC solid solutions of all pairs of ...the constituent elements. However, first principles total energy calculations for the binaries reveal a set of distinct energy minimizing structures implying the likelihood of chemically ordered low-temperature phases. We apply a hybrid Monte Carlo and molecular dynamics method to evaluate the temperature-dependent chemical order. Monte Carlo species swaps allow for equilibration of the structure that cannot be achieved by conventional molecular dynamics. At 300 K (27 °C), a cesium-chloride ordering emerges between mixed (Nb,Ta) sites and mixed (Mo,W) sites. This order is lost at elevated temperatures.
We identify a normative paradox of responsible management education. Business educators aim to promote social values and develop ethical habits and socially responsible mindsets through education, ...but they attempt to do so with theories that have normative underpinnings and create actual normative effects that counteract their intentions. We identify a limited conceptualization of freedom in economic theorizing as a cause of the paradox. Economic theory emphasizes individual freedom and understands this as the freedom to choose from available options (a view that can be characterized as quantitative, negative freedom). However, conceptualizing individuals as profit-maximizing actors neglects their freedom to reflect on the purposes and goals of their actions (a qualitative, potential view of freedom). We build on the work of pragmatist philosopher John Dewey, who distinguishes between habitualized and creative problem-solving behaviors (theory of action), conceptualizes knowledge construction as a process of interdependent scientific social inquiry (epistemology), and understands actors as having the freedom to determine what kind of people they wish to be (ethics). We apply pragmatist theory to business education and suggest equipping students with a plurality of theories, supplementing neoclassical economics with other economic perspectives (e.g., Post-Keynesian, Marxist, ecological, evolutionary, and feminist economics) and views from other disciplines (e.g., sociology, psychology, and political science) on economic behavior. Moreover, we suggest putting students into learning situations that require practical problem solution through interdependent social inquiry (e.g., using cases and real-world business projects), encouraging ethical reflection. In doing so, we contribute by linking the problematic conceptions of freedom identified in economic theorizing to the debate on responsible management education. We conceptualize a pragmatist approach to management education that explicitly re-integrates the freedom to discursively reflect on the individual and societal purpose of business activity and thereby makes existing tools and pedagogies useful for bringing potential freedom back into business.
Magnesium hydride is considered to be one of the most interesting alternatives for the reversible storage of hydrogen. It is abundant, inexpensive, easy to handle, environmentally benign and exhibits ...a high hydrogen storage capacity of up to 7.6 wt.%. Furthermore, nanocrystalline Mg powder prepared by high energy ball milling and the addition of suitable catalysts shows very fast absorption and desorption kinetics. The thermal stability of the nanocrystalline microstructure as well as the respective sorption kinetics of ball-milled MgH
2 with or without 0.5 mol% Nb
2O
5 as catalyst have been investigated after cycling and annealing at the technically relevant temperatures between 300 and 400
°
C. While kinetics for pure MgH
2 slows down substantially already after a few cycles at 300
°
C, MgH
2 with Nb
2O
5 catalyst still shows fast sorption kinetics after annealing up to 370
°
C. At higher temperatures, the kinetics for the catalyzed material also breaks down, which is attributed to a deterioration of the catalyst. Continuous coarsening of the microstructure during annealing leads to an increased fraction of the storage capacity that can only be recharged at a slower rate. This is discussed in terms of retarded growth conditions for the MgH
2 phase.
CST is widely disregarded in the academic and public discourse. This essay argues that this is the case for two related reasons. Firstly, CST is based on the pre-Enlightenment approach to moral ...philosophy, virtue ethics, while the mainstream in business ethics favours the rule-based approaches consequentialism and deontology and their variants. Secondly, mainstream approaches also have adopted a positivist epistemology where theories represent the Truth that must not be questioned: they have become ideologies. This paper argues that CST, mainly through the virtue ethical doctrine of the mean, is saved from having become an ideology and is much closer to the ideal of science as a self-questioning system than the mainstream in business ethics. This essay explains this counter-intuitive conclusion by tracing the history of CST and embedding it in an epistemic discussion and then suggesting what business ethics could take from CST to regain the all-important discursiveness it once had.
Solving the electronic structure from a generalized or standard eigenproblem is often the bottleneck in large scale calculations based on Kohn–Sham density-functional theory. This problem must be ...addressed by essentially all current electronic structure codes, based on similar matrix expressions, and by high-performance computation. We here present a unified software interface, ELSI, to access different strategies that address the Kohn–Sham eigenvalue problem. Currently supported algorithms include the dense generalized eigensolver library ELPA, the orbital minimization method implemented in libOMM, and the pole expansion and selected inversion (PEXSI) approach with lower computational complexity for semilocal density functionals. The ELSI interface aims to simplify the implementation and optimal use of the different strategies, by offering (a) a unified software framework designed for the electronic structure solvers in Kohn–Sham density-functional theory; (b) reasonable default parameters for a chosen solver; (c) automatic conversion between input and internal working matrix formats, and in the future (d) recommendation of the optimal solver depending on the specific problem. Comparative benchmarks are shown for system sizes up to 11,520 atoms (172,800 basis functions) on distributed memory supercomputing architectures.
Program title: ELSI Interface
Program Files doi:http://dx.doi.org/10.17632/y8vzhzdm62.1
Licensing provisions: BSD 3-clause
Programming language: Fortran 2003, with interface to C/C++
External routines/libraries: MPI, BLAS, LAPACK, ScaLAPACK, ELPA, libOMM, PEXSI, ParMETIS, SuperLU_DIST
Nature of problem: Solving the electronic structure from a generalized or standard eigenvalue problem in calculations based on Kohn–Sham density functional theory (KS-DFT).
Solution method: To connect the KS-DFT codes and the KS electronic structure solvers, ELSI provides a unified software interface with reasonable default parameters, hierarchical control over the interface and the solvers, and automatic conversions between input and internal working matrix formats. Supported solvers are: ELPA (dense generalized eigensolver), libOMM (orbital minimization method), and PEXSI (pole expansion and selected inversion method).
Restrictions: The ELSI interface requires complete information of the Hamiltonian matrix.
Recent work has identified a non-zinc-blende-type quaternary semiconductor, Cu2BaSnS4–x Se x (CBTSSe), as a promising candidate for thin-film photovoltaics (PVs). CBTSSe circumvents difficulties of ...competing PV materials regarding (i) toxicity (e.g., CdTe), (ii) scarcity of constituent elements (e.g., Cu(In,Ga)(S,Se)2/CdTe), and (iii) unavoidable antisite disordering that limits further efficiency improvement (e.g., in Cu2ZnSnS4–x Se x ). In this work, we build on the CBTSSe paradigm by computationally scanning for further improved, earth-abundant and environmentally friendly thin-film PV materials among the 16 quaternary systems I2–II–IV–VI4 (I = Cu, Ag; II = Sr, Ba; IV = Ge, Sn; VI = S, Se). The band structures, band gaps, and optical absorption properties are predicted by hybrid density-functional theory calculations. We find that the Ag-containing compounds (which belong to space groups I222 or I4̅2m) show indirect band gaps. In contrast, the Cu-containing compounds (which belong to space group P31/P32 and Ama2) show direct or nearly direct band gaps. In addition to the previously considered Cu2BaSnS4–x Se x system, two compounds not yet considered for PV applications, Cu2BaGeSe4 (P31) and Cu2SrSnSe4 (Ama2), show predicted quasi-direct/direct band gaps of 1.60 and 1.46 eV, respectively, and are therefore most promising with respect to thin-film PV application (both single- and multijunction). A Cu2BaGeSe4 sample, prepared by solid-state reaction, exhibits the expected P31 structure type. Diffuse reflectance and photoluminescence spectrometry measurements yield an experimental band gap of 1.91(5) eV for Cu2BaGeSe4, a value slightly smaller than that for Cu2BaSnS4.
Adam Smith’s is often falsely portrayed as having argued that radical selfishness is a force for the good and that this “invisible hand’ is his market mechanism. This paper argues that Smith’s real ...market mechanism, the sympathy manoeuvre, is a viable alternative to Schumpeterian and mainstream models of innovation in economics and also could help build a firmer theoretical basis for other approaches such as Responsible Innovation. To Smith all human activity was social and must be understood and explained in terms of the sentiments involved. Discovery, for instance, is driven by three sentiments (wonder, surprise, admiration), economic activities by sympathetic imagination, the need for exchange, the need to better one’s position in life, and the need for gratitude. Through sympathetic imagination, his famous model of the impartial spectator, Smith elegantly connects the individual and society. Smith’s innovation process is thus an exercise in social construction and not a destructive process based on radical selfishness. The paper argues that this social innovation process is a viable alternative to the extant approaches that are essentially asocial and amoral (economism) or ideologically normative (Responsible Innovation).
The paper takes a fresh look at two essays that Adam Smith wrote at the very beginning of his career. In these essays, Smith explains his philosophy of science, which is social constructivist. A ...social constructivist reading of Smith strengthens the scholarly consensus that The Wealth of Nations (WN) needs to be interpreted in light of the general moral theory he explicates in The Theory of Moral Sentiments (TMS), as the two essays and TMS stress the importance of the same concepts: e.g., moral imagination, the socially embedded individual, and humility. The connecting tissue between all three works is made up of sentiments and values. Smith regards the socially embedded human as the agent in all three realms (knowledge creation, morality, economics), and humans are always driven by values. Smith not only conceives of economics as an applied moral philosophy, but also bases both research areas on a view of knowledge creation that stresses specific epistemic values. If mainstream economic theory (and business theory that is based on it) wants to have any claim to Adam Smith, it would have to change not only what it argues but also how it argues. Economists would have to replace the language of mathematics with the language and logic of moral philosophy and give values centre stage.
Rationality and reason are often used as synonyms, although they are very different concepts. In this article we argue that rationality is the concept of reason that has been stripped of its human ...elements. Ancient and medieval philosophers such as Aristotle and Aquinas stressed that the concept of reason is composed of sensitive, discursive, and moral elements. Post-Enlightenment thinkers instead, building on the works of René Descartes and Isaac Newton, took these out and claimed that rationality must be based on an external logic devoid of value-concepts such as perfection, harmony, meaning and aim (Koyré in From the closed world to the infinite universe, The Johns Hopkins University Press, Baltimore, 1957). The purpose of this essay is to highlight this shift in Western thought and its consequences for management theories. While explaining the ancient concept of reason in contrast with modern rationalism (Klein in: Williamson RB, Zuckerman E (eds) Jacob Klein—lectures and essays, St. John’s College Press, Annapolis, 1985), we aim at raising awareness of the differences between building a research programme (especially in business sciences like economics and management) on rationality or on reason.
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