Aristotle's theory of truth, which has been the most influential account of the concept of truth from Antiquity onwards, spans several areas of philosophy: philosophy of language, logic, ontology and ...epistemology. In this 2004 book, Paolo Crivelli discusses all the main aspects of Aristotle's views on truth and falsehood. He analyses in detail the main relevant passages, addresses some well-known problems of Aristotelian semantics, and assesses Aristotle's theory from the point of view of modern analytic philosophy. In the process he discusses most of the literature on Aristotle's semantic theory to have appeared in the last two centuries. His book vindicates and clarifies the often repeated claim that Aristotle's is a correspondence theory of truth. It will be of interest to a wide range of readers working in both ancient philosophy and modern philosophy of language.
Deactivation due to coking limits the lifetime of zeolite catalysts in the production of chemicals and fuels. Superior performance can be achieved through hierarchically structuring the zeolite ...porosity, yet no relation has been established between the mesopore architecture and the catalyst lifetime. Here we introduce a top-down demetallation strategy to locate mesopores in different regions of MFI-type crystals with identical bulk porous and acidic properties. In contrast, well-established bottom-up strategies as carbon templating and seed silanization fail to yield materials with matching characteristics. Advanced characterization tools capable of accurately discriminating the mesopore size, distribution and connectivity are applied to corroborate the concept of mesopore quality. Positron annihilation lifetime spectroscopy proves powerful to quantify the global connectivity of the intracrystalline pore network, which, as demonstrated in the conversions of methanol or of propanal to hydrocarbons, is closely linked to the lifetime of zeolite catalysts. The findings emphasize the need to aptly tailor hierarchical materials for maximal catalytic advantage.
Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of ...hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact.
Some philosophers argue that false speech and false belief are impossible. In the Sophist, Plato addresses this 'falsehood paradox', which purports to prove that one can neither say nor believe ...falsehoods (because to say or believe a falsehood is to say or believe something that is not, and is therefore not there to be said or believed). In this book Paolo Crivelli closely examines the whole dialogue and shows how Plato's brilliant solution to the paradox is radically different from those put forward by modern philosophers. He surveys and critically discusses the vast range of literature which has developed around the Sophist over the past fifty years, and provides original solutions to several problems that are so far unsolved. His book will be important for all who are interested in the Sophist and in ancient ontology and philosophy of language more generally.
The introduction of a KF postdeposition treatment (KF PDT) of Cu(In,Ga)Se2 (CIGS) thin films has led to the achievement of several consecutive new world record efficiencies up to 21.7% for the CIGS ...solar cell technology. The beneficial effect of the KF PDT on the photovoltaic parameters was observed by several groups in spite of differing growth methods of the CIGS layer. For CIGS evaporated at lower temperature on alkali-free, flexible plastic substrates, a postdeposition treatment to add Na was already successfully applied. However, with the introduction of additional KF under comparable conditions, distinctly different influences on the final absorber alkali content as well as surface properties are observed. In this work we discuss in more detail the intrinsically different role of both alkali-treatments by combining several microstructural and compositional analysis methods. The ion exchange of Na by K in the bulk of the absorber is carefully analyzed, and further evidence for the formation of a K-containing layer on the CIGS surface with increased surface reactivity is given. These results shall serve as a basis for the further understanding of the effects of alkali PDT on CIGS and help identify research needs to achieve even higher efficiencies.
A vector portal between the Standard Model and the dark sector is a predictive and compelling framework for thermal dark matter. Through co-annihilations, models of inelastic dark matter (iDM) and ...inelastic Dirac dark matter (i2DM) can reproduce the observed relic density in the MeV to GeV mass range without violating cosmological limits. In these scenarios, the vector mediator behaves like a semi-visible particle, evading traditional bounds on visible or invisible resonances, and uncovering new parameter space to explain the muon
(
g
-
2
)
anomaly. By means of a more inclusive signal definition at the NA64 experiment, we place new constraints on iDM and i2DM using a missing energy technique. With a recast-based analysis, we contextualize the NA64 exclusion limits in parameter space and estimate the reach of the newly collected and expected future NA64 data. Our results motivate the development of an optimized search program for semi-visible particles, in which fixed-target experiments like NA64 provide a powerful probe in the sub-GeV mass range.
An exact knowledge of the architecture of complex pore networks and the impact on transport processes is critical to understand and optimize their integration in many functional solids. Here, a ...robust and versatile approach is demonstrated to quantitatively map pore constrictions within hierarchical faujasite‐type (Y and USY) zeolites, the most widely applied zeolitic materials in industry. Differential hysteresis scanning measurements by high‐resolution argon sorption coupled with an advanced modeling framework enable the derivation of the amount and size of pyramidal, constricted, and occluded mesopores. This yields unprecedented insight into the impact of widely practiced demetallation treatments on the porosity evolution and clearly highlights the interplay between the geometry of mesopores developed by a given treatment and those introduced by previously applied postsynthetic modifications. Based on the findings, the dynamic assessment by positron annihilation spectroscopy confirms the effectiveness of each mesopore type at enhancing the diffusion of ortho‐positronium within the crystal. The quantitative descriptors attained by these complementary techniques can revolutionize the design of porous materials for a wide range of applications.
Differential hysteresis scanning and positron annihilation spectroscopy are combined to quantify the architecture and effectiveness of complex pore networks in a challenging set of faujasite zeolites with hierarchical porosity. Correlation of the pore geometry with the enhanced diffusion of ortho‐positronium emphasizes the importance of improved porosity descriptors. This powerful approach is applicable to any complex porous material integrating micro and/or mesopores.
Update of Muonium 1S–2S transition frequency Cortinovis, Irene; Ohayon, Ben; de Sousa Borges, Lucas ...
The European physical journal. D, Atomic, molecular, and optical physics,
2023/4, Volume:
77, Issue:
4
Journal Article
Peer reviewed
Open access
We present an updated value of the Muonium 1
S
–2
S
transition frequency, highlighting contributions from different QED corrections as well as the large uncertainty in the Dirac contribution, ...stemming from the uncertainty of the electron to muon mass ratio. Improving the measurement of this spectral line would allow to extract a more accurate determination of fundamental constants, such as the electron to muon mass ratio or, combined with the Muonium hyperfine splitting, an independent value of the Rydberg constant. Furthermore, we report on the current status of the Mu-MASS experiment, which aims at measuring the Muonium 1
S
–2
S
transition frequency at a
10
kHz
uncertainty level.
Graphic abstract
Muonium is a hydrogen like bound system with a positive muon and an electron. Here the authors measure the Lamb shift and frequency of the transition from 2S1/2, F = 0 state to 2P1/2, F = 1 state in ...muonium atom and the hyperfine structure of the 2S level.
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