The creep rupture properties of DD419 single crystal superalloys，fabricated at varying pouring temperatures were examined under conditions of 850 ℃/650 MPa，1050 ℃/190 MPa and 1100 ℃/130 MPa. SEM，EDS and TEM were used to analyze the microstructure and component segregation to study their effects on the durability. The results show that as the pouring temperature decreases，the primary dendrite spacing of the alloy widens，the eutectic content and the number of micropore increase，and the γ′ phase size diminishes. Under high temperature/low stress（1100℃/130 MPa），the γ′ phase size exerts a more pronounced influence on durability than do micropore and residual eutectic content. The finely dispersed γ′ phase enhances the alloy’s durability under all three test scenarios，with the alloy poured at 1500 ℃ exhibiting optimal durability. At intermediate temperature/high stress condition（1050℃/190 MPa），the γ′ phase is intersected by numerous dislocations, and dispersed γ′ phase may contribute to dislocation pile-ups. Concurrently，the alloy maintains good elongation at different pouring temperatures；however，as the pouring temperature decreases，section shrinkage decreases under all three test conditions. Pouring temperature has a negligible impact on the the alloy’s fracture morphology. Specifically, the γ′ phase near the fracture surface of the specimen tested under 850 ℃/650 MPa condition remains cubic morphology，with a mixed -mode fracture mechanism. Under other durability parameters，the γ′ phase assumes a rafted configuration，leading to an all-micropore aggregation fracture mechanism.
Property elicitation studies which attributes of a probability distribution can be determined by minimizing a risk. We investigate a generalization of property elicitation to imprecise probabilities (IP). This investigation is motivated by distributionally robust optimization and multi-distribution learning. Both those frameworks replace the minimization of a single risk over a (precise) probability by a maximin risk minimization over a set of probabilities -- i.e. an IP. We show what can be learned in those multi-distribution setups by providing necessary and sufficient conditions for the elicitability of an IP-property. Central to these conditions is the observation made in related literature that the elicited IP-property is the corresponding classical property of the probability in the IP with the maximum Bayes risk.
A nonzero element of an integral domain (or commutative cancellative monoid) is called atomic if it can be written as a finite product of irreducible elements (also called atoms). In this paper, we introduce and investigate an unrestricted version of the finite factorization property, extending the work on unrestricted UFDs carried out by Coykendall and Zafrullah who first studied unrestricted. An integral domain is said to have the unrestricted finite factorization (U-FF) property if every atomic element has only finitely many factorizations, or equivalently, if its atomic subring is a finite factorization domain (FFD). We position the property U-FF within the hierarchy of classical finiteness conditions, showing that every IDF domain is U-FF but not conversely, and we analyze its behavior under standard constructions. In particular, we determine necessary and sufficient conditions for the U-FF property to ascend along $D+M$ extensions, prove that nearly atomic IDF domains are FFDs, and construct an explicit example of an integral domain with the U-FF property whose polynomial ring is not U-FF. These results demonstrate that the U-FF property behaves analogously to the IDF property, while providing a finer interpolation between the IDF and the FF conditions.
In this paper, T-joints of Ti-6Al-3Nb-2Zr-1Mo titanium alloy were joined with friction stir welding, and microstructure evolution and forming mechanism were studied. The effect of using tungsten inert gas welding to heat additionally the FSW was investigated. Results show a strong effection microstructure of stir zone (SZ) due to the temperature gradient and fast cooling rate. The top and middle sections of SZ have a basketweave microstructure, while there is duplex microstructure at the bottom. When welding at 750 rpm-50 mm/min, the maximum tensile strength of the joint is similar to that of the base metal (BM). As the heat input increases, grain coarsening occurs, which reduces the joint tensile strength and the ability to plastically deform. The fracture mode changes from mixed fracture to ductile one. When TIG-assisted heat source is 20 mm in front of the tool and the power input is in 600 W, the temperature field produced is relatively uniform, which has a positive effect on the weld.
Recently, Widmer introduced a new sufficient criterion for the Northcott property on the finiteness of elements of bounded height in infinite algebraic extensions of number fields. We provide a simplification of Widmer's criterion when the extension is abelian, and use this to exhibit fields with the Northcott property that do not satisfy Widmer's new criterion. We also show how the construction of pseudo algebraically closed fields with the Northcott property, carried out in previous work using the first version of Widmer's criterion, can be simplified.
In this paper, we introduce and study the spectral property $(E_A)$. This property means that the difference between the approximate point spectrum and the upper semi-Fredholm spectrum coincides with the difference between the approximate point spectrum and the upper semi-Weyl spectrum. Together with local spectral theory, we explore the behavior of this property under certain topological conditions and derive characterizations for the operators that verify it. Furthermore, we establish sufficient conditions that guarantee that a bounded linear operator verifies the property $(E_A)$.
Objective: South Africa is a country with great potential for intensive development due to the active growth and adoption of digital technologies. The rapidly emerging digital landscape is transforming the legal framework, which in turn influences the digital environment. This transformative relationship determined the focus of the research, which is to identify the legal system adaptability under dynamic changes, as well as the legal landscape evolution under digitalization and technological progress.Methods: the study of the changing legal landscape required an interdisciplinary approach that combines legal analysis with ideas from sociology, economics, etc. In doing so, the formal-legal method was used to examine the key legal instruments shaping South Africa's digital environment and providing the opportunities and challenges of the interaction between digital technologies and South African law.Results: the paper provides insights into how the South African legal system is addressing digital challenges; assesses the integration of digital innovations into the legal system; highlights the transformative impact of digital technologies on traditional legal processes, including collecting evidence, dispute resolution and access to justice. Finally, it evaluates the role of digital technologies in making legal processes more efficient.Scientific novelty: the study contributes to the ongoing debate on the complex relationship between digital technologies and South African law. It shows how South African law is coping with digital complexities and substantiates new insights into the transformation of the traditional legal paradigm as a result of digitalization, as well as its implications for legal proceedings and access to justice. By delving into the adaptations, challenges and innovations arising at the intersection of law, technologies and digitalization, insights are gained into how South African law navigates the dynamic digital landscape.Practical significance: adapting the legal landscape to digitalization and technological advances is critical to ensure rapid technological progress. It also requires collaboration between government agencies, civil society, experts in law and technology. The study provides valuable recommendations and suggestions for policymakers, legal practitioners and stakeholders shaping South Africa's legal ecosystem. The author addresses the challenges of ensuring personal data privacy, enhancing electronic interactions, and countering cybercrime. The importance of introducing technological achievements while maintaining robust legal safeguards is emphasized.
We contribute to the study of generalizations of the Perfect Set Property and the Baire Property to subsets of spaces of higher cardinalities, like the power set $P(λ)$ of a singular cardinal $λ$ of countable cofinality or products $\prod_{i<ω}λ_i$ for a strictly increasing sequence $\langleλ_i ~ \vert ~ i<ω\rangle$ of cardinals. We consider the question under which large cardinal hypotheses classes of definable subsets of these spaces possess such regularity properties, focusing on rank-into-rank axioms and classes of sets definable by $Σ_1$-formulas with parameters from various collections of sets. We prove that $ω$-many measurable cardinals, while sufficient to prove the Perfect Set Property of all $Σ_1$-definable sets with parameters in $V_λ\cup\{V_λ\}$, are not enough to prove it if there is a cofinal sequence in $λ$ in the parameters. For this conclusion, the existence of an I2-embedding is enough, but there are parameters in $V_{λ+1}$ for which I2 is still not enough. The situation is similar for the Baire Property: under I2 all sets that are $Σ_1$-definable using elements of $V_λ$ and a cofinal sequence as parameters have the Baire property, but I2 is not enough for some parameter in $V_{λ+1}$. Finally, the existence of an I0-embedding implies that all sets that are $Σ^1_n$-definable with parameters in $V_{λ+1}$ have the Baire property.
Summary: Due to lack of the kernel awareness, some popular deep image reconstruction networks are unstable. To address this problem, here we introduce the bounded relative error norm (BREN) property, which is a special case of the Lipschitz continuity. Then, we perform a convergence study consisting of two parts: (1) a heuristic analysis on the convergence of the analytic compressed iterative deep (ACID) scheme (with the simplification that the CS module achieves a perfect sparsification), and (2) a mathematically denser analysis (with the two approximations: [1] AT is viewed as an inverse A-1 in the perspective of an iterative reconstruction procedure and [2] a pseudo-inverse is used for a total variation operator H). Also, we present adversarial attack algorithms to perturb the selected reconstruction networks respectively and, more importantly, to attack the ACID workflow as a whole. Finally, we show the numerical convergence of the ACID iteration in terms of the Lipschitz constant and the local stability against noise. The bigger picture: For deep tomographic reconstruction to realize its full potential in practice, it is critically important to address the instabilities of deep reconstruction networks, which were identified in a recent PNAS paper. Our analytic compressed iterative deep (ACID) framework has provided an effective solution to address this challenge by synergizing deep learning and compressed sensing through iterative refinement. Here, we provide an initial convergence analysis, describe an algorithm to attack the entire ACID workflow, and establish not only its capability of stabilizing an unstable deep reconstruction network but also its stability against adversarial attacks dedicated to ACID as a whole. Although our theoretical results are under approximations, they shed light on the converging mechanism of ACID, serving as a basis for further investigation.
The properties of pineapple leaf fiber composites drawn from the vastly untapped Yankee pineapple plant variant were tested in this study. The properties of silane treated (T-PALFC) and untreated (UT-PALFC) samples were evaluated using flexural testing, dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA). In this study, the T-PALFC sample was specifically treated in silane for 3 hours. The results show that the bending strength is improved by up to 97% in PALF composite compared to epoxy composite.The DMA results show that the UT-PALFC possess 7.1% higher storage modulus than T-PALFC, indicating untreated fiber attribute to high dynamic property in composite. The TMA finding shows the sequence of linear coefficient of thermal expansion (CTE) as follows: T-PALFC > Neat epoxy > UT-PALFC. Furthermore, this research shows T-PALFC displayed lower properties compared to UT-PALFC because the composite had low cross-linked network. This is because T-PALFC had low glass transition temperature, Tg as shown in tan delta curve and was further supported in differential scanning calorimetry analysis. Moreover, morphological analysis of the cross-section image of the T-PALFC shows the existence of a wide gap between the PALF and the matrix compared to UT-PALFC.
Science, Textile bleaching, dyeing, printing, etc.
Objective: The New-generation trade agreements, which include the agreement with Japan, provide wide coverage – not only the liberalisation of trade in goods or services but also the protection of intellectual property rights, the public procurement market, sustainable development and others. This paper aims to demonstrate key provisions and (both ex post and ex ante) opportunities that the agreement creates for EU companies.
Research Design & Methods: The research methods include a critical review of existing literature, an analysis of relevant legal and official documents of the European Union, as well as the provisions of the EU-Japan trade agreement. The empirical research focused on Eurostat data.
Findings: The provisions of the EU-Japan agreement provide an incentive for European companies to strengthen their position on the Japanese market. The elimination of import duties and other barriers to trade in Japan in relation to certain agricultural products on the entry into force of the agreement contributed to higher exports from the EU for these groups of goods. What might be expected is the additional effect of the liberalisation of bilateral trade on third countries. In fact, standards or rules agreed by Japan and the EU may become even more attractive to third countries, as their adoption would facilitate access to two large markets.
Implications & Recommendations: Japan is a relatively important trading partner for the EU and vice versa. One of the biggest achievements of the agreement made between the European Union and Japan includes the wide and deep liberalisation of trade in goods. Despite the fact that the overall level of tariff protection is relatively low, there are still some groups of goods for which the protection in the form of customs duties constitutes an important barrier, as a result of which the conditions for competing on the partner’s market deteriorate. It seems that EU entrepreneurs should make more use of the opportunities which are created by the provisions of the free trade agreement with Japan. So far, the trade crisis caused by the pandemic has stood in the way.
Contribution & Value Added: Research conducted so far is of an ex ante nature, both regarding the provisions of the agreement (publications written before 2018) and the evaluation of its potential effects on economy, trade, production or selected sectors. The research carried out in this article is of an ex post nature; it covers the period following the entry into force of the agreement and does not present any growth scenarios or forecasts, as was the case in the existing research. The article attempted to juxtapose the provisions of the agreement with Japan with trade conditions applicable to EU companies, as well as with the growth rate, volume and coverage of bilateral trade in goods.
This paper presents a method of high-capacity and transparent watermarking based on the usage of deep neural networks with the adjustable subsquares properties algorithm to encode the data of a watermark in high-quality video using the H.265/HEVC (High-Efficiency Video Coding) codec. The aim of the article is to present a method of embedding a watermark in a video with HEVC codec compression by making changes in a video in a way that is not noticeable to the naked eye. The method presented here is characterised by focusing on ensuring the accuracy of the original image in relation to the watermarked image, providing the transparency of the embedded watermark, while ensuring its survival after compression by the HEVC codec. The article includes a presentation of the practical results of watermark embedding with a built-in variation mechanism of its capacity and resistance, thanks to the adjustable subsquares properties algorithm. The obtained PSNR (peak signal-to-noise ratio) results are at the level of 40 dB or better. There is the possibility of the complete recovery of a watermark from a single frame compressed in the CRF (constant rate factor) range of up to 16, resulting in a BER (bit error rate) equal to 0 for the received watermark.
Mandlenkosi G.R. Mahlobo, Lethu Chikosha, Peter A. Olubambi
Great efforts have been made in fabricating Ti–6Al–4V alloys that can be used in the biomedical implants industry. The increasing interest in using fabricated Ti–6Al–4V alloys in industrial applications is mainly due to the properties of alloys which include good combination of mechanical and corrosion resistance. This study was aimed at evaluating the corrosion properties of the Ti–6Al–4V alloy fabricated via powder rolling technique under various simulated human body solutions. A three-electrode electrochemical cell was used to carry out corrosion studies at 37 °C where the fabricated Ti–6Al–4V was immersed in 3.5% NaCl (pH = 6.5) and two simulated human body fluids, namely; Hank's balanced salt solution (HBSS) and Ringers solution with the measured pH of 6.9 and 6.4 respectively. The electrochemical techniques used to investigate the corrosion studies included open circuit potential (OCP), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The fabricated Ti–6Al–4V alloy was characterized before and after the corrosion experiments via X-ray diffraction (XRD) and scanning electron microscope (SEM). The potentiodynamic polarization curves revealed a passivation phenomenon on the anodic domain indicating high corrosion resistance of Ti–6Al–4V alloy in all three electrolytes. The Ti–6Al–4V alloy exhibited the highest corrosion resistance when immersed in 3.5% NaCl with the estimated corrosion rate of 0.480 μm/yr. The excellent corrosion resistance of Ti–6Al–4V alloy was mainly due to the formation of an oxide film formed on the alloy surface as deduced from the EIS analysis. No corrosion products were detected by XRD analysis on the Ti–6Al–4V alloy surface immersed in all electrolytes which confirmed an excellent corrosion resistance property.
In this article, we study the following question asked by Michael Hartz in a recent paper \cite{Hartz}: \textit{which operator spaces satisfy the column-row property?} We provide a complete classification of the column-row property for non-commutative $L_{p}$-spaces over semifinite von Neumann algebras. We study other relevant properties of operator spaces that are related to the column-row property and discuss their existence and non-existence for various natural examples of operator spaces.
The Alternating Direction Method of Multipliers (ADMM) is a popular and promising distributed framework for solving large-scale machine learning problems. We consider decentralized consensus-based ADMM in which nodes may only communicate with one-hop neighbors. This may cause slow convergence. We investigate the impact of network topology on the performance of an ADMM-based learning of Support Vector Machine using expander, and mean-degree graphs, and additionally some of the common modern network topologies. In particular, we investigate to which degree the expansion property of the network influences the convergence in terms of iterations, training and communication time. We furthermore suggest which topology is preferable. Additionally, we provide an implementation that makes these theoretical advances easily available. The results show that the performance of decentralized ADMM-based learning of SVMs in terms of convergence is improved using graphs with large spectral gaps, higher and homogeneous degrees.