Dixmier property concerns the bijectivity of endomorphisms for algebras. We introduce a relative Dixmier property, which is a generalization of the Dixmier property. This new concept has applications in proving that several classes of Poisson algebras possess the Dixmier property, as well as in other topics such as the cancellation problem and the non-existence of Hopf coactions.
Let $(A,G,α)$ be a partial dynamical system and let $A\rtimes_{α,r} G$ denote the associated reduced partial crossed product. In this article, we introduce the Haagerup property for partial actions of discrete groups on $C^*$-algebras. We prove that the partial crossed product $A\rtimes_{α,r} G$ has the Haagerup property if and only if both $A$ and the partial action $α$ have the Haagerup property. As a consequence, we obtain an equivalence between the Haagerup property of the partial crossed product and that of the underlying $C^*$-algebra and the acting group. We also show that the Haagerup property is preserved under inductive limits and apply this result to study the Haagerup property of inductive limits of partial crossed products.
Heusler alloys, which were unintentionally discovered at the start of the 20th century, have become intriguing materials for many extraordinary functional applications in the 21st century, including smart devices, spintronics, magnetic refrigeration and the shape memory effect. With this review article, we would like to provide a comprehensive review on the recent progress in the development of Heusler alloys, especially Ni-Mn based ones, focusing on their structural crystallinity, order-disorder atoms, phase changes and magnetic ordering atoms. The characterization of the different structures of these types of materials is needed, where a detailed exploration of the crystal structure is presented, encompassing the influence of temperature and compositional variations on the exhibited phases. Hence, this class of materials, present at high temperatures, consist of an ordered austenite with a face-centered cubic (FCC) superlattice as an L2<sub>1</sub> structure, or body-centered cubic (BCC) unit cell as a B2 structure. However, a low-temperature martensite structure can be produced as an L10, 10M or 14M martensite structures. The crystal lattice structure is highly dependent on the specific elements comprising the alloy. Additionally, special emphasis is placed on phase transitions within Heusler alloys, including martensitic transformations ranging above, near or below room temperature and magnetic transitions. Therefore, divers’ crystallographic defects can be presented in such types of materials affecting their structural and magnetic properties. Moreover, an important property of Heusler compounds, which is the ability to regulate the valence electron concentration through element substitution, is discussed. The possible challenges and remaining issues are briefly discussed.
Sandeep Kumar Sahoo, Jogendra Majhi, Suresh Chandra Patnaik
et al.
Abstract Aluminium matrix composites (AMCs) are well known for their excellent wear resistance and low weight. In the present work, in-situ synthesis of Al-Si-TiB2 composites with near eutectic and hypereutectic compositions of Al-Si alloys has been attempted through salt-metal reaction (K2TiF6 and KBF4 halide salts) by stir casting route. The fabricated composites were subjected to microstructure analysis, XRD study, sliding wear test, hardness and density measurements. The combined effect of Si and TiB2 is the novelty of this investigation to alter the structure–property correlation as well as hardness and tribological properties. Optical Emission Spectroscopy analysis indicated some amount of Si loss during stir casting and revealed the final composition of the cast composites. Though the increase in the density of the composite was not considerable due to incorporation of TiB2 particles, there was remarkable improvement in hardness and tribological properties attributed to clear interface between the matrix and the reinforcement as a result of in-situ process of fabrication. Wear resistance was found to be improved with increasing amount of Si content with a fixed TiB2 content in the composites under a constant load. TiB2 acts as a good grain refiner and improves the wear properties of the hypereutectic Al-Si alloy composites by decreasing the brittle primary silicon particle size.
Materials of engineering and construction. Mechanics of materials
Most bamboo composites are designed referring to the specifications of wood structures. However, this approach is inadequate due to the volume difference between bamboo bundles and other fibers. Previous studies have investigated the effects of strand size of parallel strand bamboo (PSB) in tension and compression. Here, to investigate the impact of varying span-height ratio on the flexural characteristics of PSB, specimens with five different section heights were designed. Numerical simulations were performed to reveal the deformation, the failure process, and the load carrying ability of the PSB beams. The first-order anisotropic beam theory was applied to predict the internal forces. The results show that the bending property of the PSB is closely related to the section height. It is recommended that the dimension of length × width × height (300 mm × 20 mm × 30 mm) should be the most appropriate specimen size for the bending experiment. The error between the theoretical value and the test value was only about 0.4%. These endeavors can facilitate the establishment of bending test standards for bamboo structures.
In the field of non-destructive testing (NDT) for concrete structures, the traditional air-coupled impact-echo technology often has the problems of complex operation and low efficiency. In order to solve these problems, this study uses Comsol software to establish a finite element model (FEM) of the concrete structure with different void sizes and obtains the variation rule of peak frequency. The recognition property of the concrete void based on peak frequency is proposed, which is explained and validated by relevant theory and experiments. The results show that compared with the depth of the void, the influence of the void width on the peak frequency increases significantly. When the void width is greater than 0.3 m, the peak frequency of the sound wave decreases with the increase in the width, and the change is obvious. This paper describes the applicability of concrete void depth less than 0.4 m for the air-coupled method and, when the concrete void depth is less than 0.4 m, the peak frequency can be used to effectively identify void widths greater than 0.3 m. The research results will be beneficial to void detection of concrete structures such as tunnel lining and pavements.
Samuel G. Evans, Tim G. Holland, Jonathan W. Long
et al.
Across the United States, wildfire severity and frequency are increasing, placing many properties at risk of harm or destruction. We quantify and compare how different forest management strategies designed to increase forest resilience and health reduce the number of properties at risk from wildfire, focusing on the Lake Tahoe Basin of California and Nevada. We combine landscape change simulations (including climate change, wildfire, and management effects) with scenarios of current and plausible fuel treatment activities and parcel-scale fire risk analysis. Results suggest that more aggressive fuel treatment activities that treat more area on the landscape, whether through mechanical and hand thinning or prescribed fire, dramatically lower the fire probability in the region and lead to a corresponding lower risk of property loss. We estimate that relative to recent practices of focusing management in the wildland–urban interface, more active forest management can reduce property loss risk by 45%–76%, or approximately 2600–4900 properties. The majority of this risk reduction is for single family residences, which constitute most structures in the region. Further, we find that the highest risk reduction is obtained through strategies that treat a substantially greater area than is currently treated in the region and allows for selective wildfires to burn for resource objectives outside of the wildland–urban interface. These results highlight the importance of more active forest management as an effective tool in reducing the wildfire risk to capital assets in the region.
Andrea Fernández-Nieto, Sagrario Muñoz, Vicenta María Barragán
The alcohol permeability of anion exchange membranes is a crucial property when they are used as a solid electrolyte in alkaline direct alcohol fuel cells and electrolyzers. The membrane is the core component to impede the fuel crossover and allows the ionic transport, and it strongly affects the fuel cell performance. The aim of this work is to compare different anion exchange membranes to be used as an electrolyte in alkaline direct alcohol fuels cells. The alcohol permeability of four commercial anion exchange membranes with different structure were analyzed in several hydro-organic media. The membranes were doped using different types of alkaline doping agents (LiOH, NaOH, and KOH) and different conditions to analyze the effect of the treatment on the membrane behavior. Methanol, ethanol, and 1-propanol were analyzed. The study was focused on the diffusive contribution to the alcohol crossover that affects the fuel cell performance. To this purpose, alcohol permeability was determined for various membrane systems. The results show that membrane alcohol permeability is affected by the doping conditions, depending on the effect on the type of membrane and alcohol nature. In general, heterogeneous membranes presented a positive correlation between alcohol permeability and doping capacity, with a lower effect for larger-size alcohols. A definite trend was not observed for homogeneous membranes.
Francesco Aldo Costabile, Maria Italia Gualtieri, Anna Napoli
The <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>δ</mi><mn>2</mn></msup><mrow><mo>(</mo><mo>·</mo><mo>)</mo></mrow></mrow></semantics></math></inline-formula> operator, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>δ</mi><mo>(</mo><mo>·</mo><mo>)</mo></mrow></semantics></math></inline-formula> is the known central difference operator, is considered. The associated odd and even polynomial sequences are determined and their generalizations studied. Particularly, matrix and determinant forms, recurrence formulas, generating functions and an algorithm for effective calculation are provided. An interesting property of biorthogonality is also demonstrated. New examples of odd and even central polynomial sequences are given.
Elastodynamic problems are investigated in this work by employing the enriched finite element method (EFEM) with various enrichment functions. By performing the dispersion analysis, it is confirmed that for elastodynamic analysis, the amount of numerical dispersion, which is closely related to the numerical error from the space domain discretization, can be suppressed to a very low level when quadric polynomial bases are employed to construct the local enrichment functions, while the amount of numerical dispersion from the EFEM with other types of enrichment functions (linear polynomial bases or first order of trigonometric functions) is relatively large. Consequently, the present EFEM with a quadric polynomial enrichment function shows more powerful capacities in elastodynamic analysis than the other considered numerical techniques. More importantly, the attractive monotonic convergence property can be broadly realized by the present approach with the typical two-step Bathe temporal discretization technique. Three representative numerical experiments are conducted in this work to verify the abilities of the present approach in elastodynamic analysis.
Abstract What can intellectual property (IP) learn from the questions raised by property doctrine? A lot of scholarship addresses the degree to which the two bodies of law cohere in principle, justification, or practice. This chapter surveys some of this well-marked terrain, while suggesting some less detailed areas of the map that might merit more exploration than they have received to date. The most familiar set of questions arise from the contention that IP is or should be considered a form of property, but property law is also a source of doctrines and approaches for limiting the scope of intellectual property rights. Though less emphasized, a concern with information also links the two fields, as many property doctrines may also be considered a form of information management. Finally, conceiving of property doctrine as a system offers another possibility for informing IP scholarship.
Copyright as an exclusive right for the creator or copyright holder to carry out the results of his ideas or ideas in the form of specific information or certain. Basically, copyright is the right to copy, adapt or produce a work, copyright is possible for the right holder to limit the copying or in any form without the illegitimate permission of a work, it can be realized by registration copyright, in its application, of course, there are obstacles that exist in the enforcement of copyright law itself. One example is the lack of awareness in registration copyright of songs by the creator. The research objective was to determine and analyze the legal awareness of regional pop songwriters to register their copyright. The research method uses normative research through a conceptual approach and a statue approach. The results show that the composers of regional pop songs know the importance of recording copyright because it is in accordance with the mandate of Act No. 28 of 2014 concerning Copyright and has also participated in the socialization carried out by the Ministry of Law and Human Rights, but songwriters do not record their work. Some songwriters consider that the registration is of no use because, from an economic standpoint, they cannot profit or lose personally, besides that their aspirations have not been fully channeled by the related institutions they shelter in this case the Collective Management Institute. Therefore to decide on the sale of the song's copyrighted work rather than registering it to the Ministry of Law and Human Rights in the Field of Intellectual Property.
Aditi S. Krishnapriyan, Joseph Montoya, Maciej Haranczyk
et al.
Abstract Machine learning has emerged as a powerful approach in materials discovery. Its major challenge is selecting features that create interpretable representations of materials, useful across multiple prediction tasks. We introduce an end-to-end machine learning model that automatically generates descriptors that capture a complex representation of a material’s structure and chemistry. This approach builds on computational topology techniques (namely, persistent homology) and word embeddings from natural language processing. It automatically encapsulates geometric and chemical information directly from the material system. We demonstrate our approach on multiple nanoporous metal–organic framework datasets by predicting methane and carbon dioxide adsorption across different conditions. Our results show considerable improvement in both accuracy and transferability across targets compared to models constructed from the commonly-used, manually-curated features, consistently achieving an average 25–30% decrease in root-mean-squared-deviation and an average increase of 40–50% in R2 scores. A key advantage of our approach is interpretability: Our model identifies the pores that correlate best to adsorption at different pressures, which contributes to understanding atomic-level structure–property relationships for materials design.
PtRh alloys are highly active in the anodic methanol oxidation reaction (MOR) but few studies have looked at their evolution in the composition and structure during the catalytic process. Herein, a uniformly dispersed carbon-supported PtRh (PtRh/C) catalyst with Rh-enriched surface was synthesized via a facial hydrothermal method. By recording the performance of different cyclic voltammetry (CV) cycles during electrocatalytic MOR process in acid, the evolution of PtRh/C in composition and structure was elucidated. During the first 80 CV cycles, the rapid dissolution of the surface Rh atoms and the exposure of active Pt sites lead to the dramatic enhancement of the current density. When further continue the CV cycling, Pt atoms on the surface have aggregated and recombined to form a tightly aligned Pt-enriched surface. But Rh tends to be stable and catalytic performance reaches a relatively stable status with slightly decreased activity. Compared with the performance of PtRu/C catalyst, it can be concluded that PtRh/C has better stability and higher activity based on the less soluble property of Rh than Ru. Keywords: PtRh alloys, Anode catalysts, Methanol electrooxidation, Structural evolution, Compositional evolution
The article deals with the issues of the legal “irregularity” of criminal and material responsibility of the “black diggers” for the illegal production of natural resources in the territory of the Kuzbass. The schemes of production and selling the coal are very different. That is why it is rather difficult to consider them in terms of criminal, arbitration, and administrative processes, especially by considering the issues of reclaiming the lands broken by such illegal activity. This is evidenced by the limited judicial practice of arbitration courts and courts of law of the Kuzbass. There is also no similar practice in other territorial subjects of the Russian Federation. Thus, there is a necessity in urgent developing of the methodical recommendations for the law enforcement officials on the calculation and compensation for the damage, considering the escalating statistical data on the illegal activity of the “black diggers”. Since the production and land reclamation caused by the coal mining are technologically interconnected, there must be an assigned surveillance of the use of a fund and the order of land reclamation to the prosecutor’s office on the surveillance of respecting the lawfulness in the coal-mining industry. These actions are provided for the coal-mining enterprises. For a long time, the “black diggers” have been producing the natural minerals which are the property of the state and they have also been able to escape the attention of the Russian legislation.
One of the problems of formal verification is that it is not functionally complete due the incompleteness of specifications. An implementation meeting an incomplete specification may still have a lot of bugs. In testing, this issue is addressed by replacing functional completeness with $\mathit{structural}$ one. The latter is achieved by generating a set of tests probing every piece of a design implementation. We show that a similar approach can be used in formal verification. The idea here is to generate a property of the implementation at hand that is not implied by the specification. Finding such a property means that the specification is not complete. If this is an $\mathit{unwanted}$ property, the implementation is buggy. Otherwise, a new specification property needs to be added. Generation of implementation properties related to different parts of the design followed by adding new specification properties produces a $\mathit{structurally}$-$\mathit{complete\:specification}$. Implementation properties are built by $\mathit{partial\: quantifier\:elimination}$, a technique where only a part of the formula is taken out of the scope of quantifiers. An implementation property is generated by applying partial quantifier elimination to a formula defining the "truth table" of the implementation. We show how our approach works on specifications of combinational and sequential circuits.
We show that the sequentially $(S_r)$ condition for simplicial complexes is a topological property. Along the way, we present an elementary proof for the fact that the Serre's condition $(S_r)$ is a topological property.
In this work, we introduce the notion of Ball dentable property in Banach spaces. We study certain stability results for the $w^*$-Ball dentable property leading to a discussion on Ball dentability in the context of ideals of Banach spaces. We prove that the $w^*$-Ball-dentable property can be lifted from an $M$-ideal to the whole Banach Space. We also prove similar results for strict ideals of a Banach space. We note that the space $C(K,X)^*$ has $w*$-Ball dentable property when $K$ is dispersed and $X^\ast$ has the $w^*$-Ball dentable property.
We introduce the notion of property signatures, a representation for programs and program specifications meant for consumption by machine learning algorithms. Given a function with input type $τ_{in}$ and output type $τ_{out}$, a property is a function of type: $(τ_{in}, τ_{out}) \rightarrow \texttt{Bool}$ that (informally) describes some simple property of the function under consideration. For instance, if $τ_{in}$ and $τ_{out}$ are both lists of the same type, one property might ask `is the input list the same length as the output list?'. If we have a list of such properties, we can evaluate them all for our function to get a list of outputs that we will call the property signature. Crucially, we can `guess' the property signature for a function given only a set of input/output pairs meant to specify that function. We discuss several potential applications of property signatures and show experimentally that they can be used to improve over a baseline synthesizer so that it emits twice as many programs in less than one-tenth of the time.