Characterization Of Property Research Articles

Coincidence Points of Parameterized Generalized Equations with Applications to Optimal Value Functions

The paper studies coincidence points of parameterized set-valued mappings (multifunctions), which provide an extended framework to cover several important topics in variational analysis and optimization that include the existence of solutions of parameterized generalized equations, implicit function and fixed-point theorems, optimal value functions in parametric optimization, etc. Using the advanced machinery of variational analysis and generalized differentiation that furnishes complete characterizations of well-posedness properties of multifunctions, we establish a general theorem ensuring the existence of parameter-dependent coincidence point mappings with explicit error bounds for parameterized multifunctions between infinite-dimensional spaces. The obtained major result yields a new implicit function theorem and allows us to derive efficient conditions for semicontinuity and continuity of optimal value functions associated with parametric minimization problems subject to constraints governed by parameterized generalized equations.

Electrochemical characterisation of catalytic property for oxygen reduction reaction on cobalt ferrite electrode

X-ray diffraction analysis of CoFe2O4 spinel’s prepared by different fuels by solution combustion method showed the formation of phase pure cobalt ferrite. Oxygen reduction reaction kinetics for the synthesised cobalt ferrites were analysed using electrochemical techniques. Among the prepared catalysts, CoFe2O4 prepared using citric acid as fuel exhibited maximum reduction current and lowest Tafel slope of 0.129 V dec−1. ORR studies revealed that the number of electrons transferred during oxygen reduction was ∼4 as determined from Koutecky–Levich plot. CoFe2O4 prepared using citric acid as fuel showed the minimum charge transfer resistance for ORR.

Hydrothermal Alteration Zones’ Magnetic Susceptibility Footprints and 3D Model of Iron Oxide-Copper-Gold (IOCG) Mineralization, Carajás Mineral Province, Brazil

Brownfield areas are important targets of exploration; however, the extensive drilling present in these areas has not fully exploited their prospective potential. The appropriate use of drill hole cores in these areas can play an important role in deep exploration. We present a case study of iron oxide-copper-gold (IOCG) Furnas Southeast deposit, located in the Carajás Mineral Province, Brazil. This deposit has disseminated chalcopyrite, bornite and gold mineralization associated with a silicic (Si), potassic (K), calcic (Na), sodic-calcic (Na-Ca) hydrothermal alteration, and intense iron metasomatism with massive magnetite (Fe) alteration. Petrophysical hand-held equipment measurements were carried out on drill core samples with the purpose of studying the potential roles that magnetic susceptibility properties can play in high-grade mineralization. The results indicate that the geological complexity of the IOCG deposit is readily reflected in the extensive variation of the measurements. The statistical analysis shows how the detailed characterization of this physical property carried out for this mineral association could effectively define and describe ore, and the magnetic susceptibility footprints of hydrothermal alteration zones. Furthermore, we were able to perform a magnetic susceptibility 3D modeling of diamagnetic, paramagnetic, and ferrimagnetic responses strictly correlated with known orebody. Thus, petrophysical analyses can form a quantitative geological criterion for ore delineation.

A review of thermoreflectance techniques for characterizing wide bandgap semiconductors’ thermal properties and devices’ temperatures

Thermoreflectance-based techniques, such as pump–probe thermoreflectance (pump–probe TR) and thermoreflectance thermal imaging (TTI), have emerged as the powerful and versatile tools for the characterization of wide bandgap (WBG) and ultrawide bandgap (UWBG) semiconductor thermal transport properties and device temperatures, respectively. This Review begins with the basic principles and standard implementations of pump–probe TR and TTI techniques, illustrating that when analyzing WBG and UWBG materials or devices with pump–probe TR or TTI, a metal thin-film layer is often required. Due to the transparency of the semiconductor layers to light sources with sub-bandgap energies, these measurements directly on semiconductors with bandgaps larger than 3 eV remain challenging. This Review then summarizes the general applications of pump–probe TR and TTI techniques for characterizing WBG and UWBG materials and devices where thin metals are utilized, followed by introducing more advanced approaches to conventional pump–probe TR and TTI methods, which achieve the direct characterizations of thermal properties on GaN-based materials and the channel temperature on GaN-based devices without the use of thin-film metals. Discussions on these techniques show that they provide more accurate results and rapid feedback and would ideally be used as a monitoring tool during manufacturing. Finally, this Review concludes with a summary that discusses the current limitations and proposes some directions for future development.

On some classical properties of normed spaces via generalized vector valued almost convergence

AbstractRecently, the authors interested some new problems on multiplier spaces of Lorentz’ almost convergence andfλ-convergence as a generalization of almost convergence.fλ-convergence is firstly introduced by Karakuş and Başar, and used for some new characterizations of completeness and barrelledness of the spaces through weakly unconditionally Cauchy series in a normed spaceXand its continuous dualX*. In the present paper, we deal withfλ-convergence to have some inclusion relations between the vector valued spaces obtained from this type convergence and corresponding classical sequence spaces, and to give new characterizations of some classical properties like completeness, reflexivity, Schur property and Grothendieck property of normed spaces. By the way, we give a characterization of finite-dimensional normed spaces.

Amalgamation and Robinson property in universal algebraic logic

Abstract There is a well-established correspondence between interpolation and amalgamation for algebraizable logics that satisfy certain additional assumptions. In this paper, we introduce the Robinson property of a logic and show that a conditionally algebraizable logic without any additional assumptions has the Robinson property if and only if the corresponding class of Lindenbaum–Tarski algebras has the amalgamation property. Moreover, we give the logical characterization of the strong amalgamation property, solving an open problem of Andréka–Németi–Sain. It is also shown that given the mentioned extra assumptions the Robinson property implies the interpolation property. As conditionally algebraizable logics cover algebraizable logics as well as various quantifier logics such as classical first order logic, our results yield a generalization of some of the results concerning interpolation and amalgamation.

Compact retractions and Schauder decompositions in Banach spaces

Let X X be a separable Banach space. We give an almost characterization of the existence of a Finite Dimensional Decomposition (FDD for short) for X X in terms of Lipschitz retractions onto generating compact subsets K K of X X . In one direction, if X X admits an FDD then we construct a Lipschitz retraction onto a small generating convex and compact set K K . On the other hand, we prove that if X X admits a “small” generating compact Lipschitz retract then X X has the π \pi -property. It is still unknown if the π \pi -property is isomorphically equivalent to the existence of an FDD. For dual Banach spaces this is true, so our results give a characterization of the FDD property for dual Banach spaces X X . We give an example of a small generating convex compact set which is not a Lipschitz retract of C [ 0 , 1 ] C[0,1] , although it is contained in a small convex Lipschitz retract and contains another one. We characterize isomorphically Hilbertian spaces as those Banach spaces X X for which every convex and compact subset is a Lipschitz retract of X X . Finally, we prove that a convex and compact set K K in any Banach space with a Uniformly Rotund in Every Direction norm is a uniform retract, of every bounded set containing it, via the nearest point map.

Characterizations of Microstructure and Properties of Dissimilar AISI 316L/9Ni Low-Alloy Cryogenic Steel Joints Fabricated by Gas Tungsten Arc Welding

Characterizations of Microstructure and Properties of Dissimilar AISI 316L/9Ni Low-Alloy Cryogenic Steel Joints Fabricated by Gas Tungsten Arc Welding

Levitin-Polyak well-posedness for vector optimization problems in linear spaces

In this paper, we deal with vector optimization problems where the images of the objective maps are given in linear spaces not endowed with any topological structure. Firstly, we propose new concepts of semicontinuity of vector-valued maps acting from metric spaces into linear ones and discuss their properties and characterizations. Next, using Zorn's Lemma and these properties, we formulate existence conditions for such problems. Then, we introduce two notions of Levitin-Polyak well-posedness for the reference problems, and study sufficient conditions for their fulfillment, as well as relationships of these notions. Finally, using the Kuratowski measure of noncompactness, several metric characterizations of such well-posedness properties for vector optimization problems are investigated. Many examples are given to analyze our results.

Electrospun Al-MOF fibers as D4 Siloxane adsorbent: Synthesis, environmental impacts, and adsorption behavior

Here, we unveil the great potential of metal-organic framework (MOF) composite fibers produced by the electrospinning method to remove D4 siloxane from gaseous solutions. The fibers are based on polyacrylonitrile (PAN) and a microporous aluminum-based MOF known as DUT-4. The electrospinning configuration and DUT-4:PAN ratio in the precursor solutions play an important role in the textural properties of the fibers. Characterizations of morphology and textural properties demonstrated that the best dispersion on the fiber surface was achieved using coaxial electrospinning with a relationship of 1:1.4 of DUT-4:PAN. The Al-MOF fiber composite was evaluated as a D4 siloxane adsorbent, reaching over 85% of the D4 siloxane uptake capacity of individual DUT-4 crystals but with faster adsorption kinetics (effective diffusion coefficient 3.31 times higher). In addition, the synthesis of the composite showed a lower environmental impact and better thermal stability than that observed for DUT-4. This work shows the novel DUT-4 fibers have an outstanding potential for siloxane removal from biogas streams.

Recent progress in optimal design of superhydrophobic surfaces

Superhydrophobic surfaces have received tremendous attention due to their extraordinary physical characteristics and potential applications in various fields. However, the design of robust superhydrophobic surfaces showing both low adhesion and high antiwetting remains a great challenge. Here, we first introduce some important parameters for the characterization of the adhesion property of superhydrophobic surfaces and its physical meaning, including the apparent contact angle, rolling angle, and hysteresis angle. Then, we summarize the antiwetting property of superhydrophobic surfaces through thermodynamic and dynamic methods, and we point out the contradiction between low adhesion and high antiwetting of superhydrophobic surfaces. To achieve a trade-off between low adhesion and high antiwetting in superhydrophobic materials, we also review the recent progress made in regard to the optimal design of superhydrophobic surfaces by using chemical modification and physical design of microstructures. Finally, we review the application of superhydrophobic surfaces for drag reduction, with a few discussions and outlook. This Research Update is expected to provide useful guidance to rationally design superhydrophobic materials with low adhesion and high antiwetting properties and, thus, speed up the development of superhydrophobic materials or anti-icing materials.

Learning-Based Subsurface Quantitative Imaging via Near-Field Scanning Microwave Microscopy

Accurate characterization of sample dielectric property is essential for scientists and engineers to analyze and evaluate the performance of the invested sample. This article proposes a learning-based (LB) method for quantitative subsurface imaging via coaxial-resonator-based near-field scanning microwave microscopy (CR-NFSMM) in a nondestructive way. To efficiently generate the database, a well-designed forward solver is critical since many samples will be included in the database, each sample needs a scanning procedure, and each scanning point involves solving the forward problem once. A fast forward problem solver is used to evaluate the tip–sample interaction in CR-NFSMM that avoids repeated meshing during the scanning process and it can apply to an arbitrary tip shape. Once the neural network is trained, it generates the reconstructed image within 1 s. Numerical and experimental results show that the proposed LB method could improve the resolution of the image and recover the dielectric properties of the subsurface perturbation pixel-by-pixel. Moreover, the proposed method outperforms the traditional objective function approach in terms of image resolution and time cost. The proposed method is promising to realize a nondestructive and real-time local dielectric evaluation of the subsurface object.

Characterization and comparison of the thermophysical property of ternary and quaternary salt mixtures for solar thermal power plant applications

Molten salts offer superior thermal properties to synthetic mineral oil, making them suitable for use directly as heat transfer fluids in solar thermal power plants. In comparison to the binary salt mixture, the ternary and quaternary salt mixtures have demonstrated the ability to attain a low melting temperature of less than 100 °C. However, the thermophysical characteristics of the ternary and quaternary salt mixtures with respect to their usage in solar thermal power plant applications have remained unclear in most literature findings. This is due to similar thermophysical behavior and limited study of quaternary salt mixtures. Therefore, to fill this gap, the processing and testing of a class of novel ternary and quaternary salt mixtures were conducted to obtain the distinct thermophysical characteristics and trade-offs of the salt mixtures. The benefits and drawbacks of each mixture type are presented. Furthermore, experimental data was utilized to develop models to predict the thermophysical properties of the salt mixtures.

Concavity Property of Minimal $$L^2$$ Integrals with Lebesgue Measurable Gain IV: Product of Open Riemann Surfaces

In this article, we present characterizations of the concavity property of minimal $$L^2$$ integrals degenerating to linearity in the case of products of analytic subsets on products of open Riemann surfaces. As applications, we obtain characterizations of the holding of equality in optimal jets $$L^2$$ extension problem from products of analytic subsets to products of open Riemann surfaces, which implies characterizations of the product versions of the equality parts of Suita conjecture and extended Suita conjecture, and the equality holding of a conjecture of Ohsawa for products of open Riemann surfaces.

Characterization of the surface charge property and porosity of track-etched polymer membranes.

As an important property of porous membranes, the surface charge property determines many ionic behaviors of nanopores, such as ionic conductance and selectivity. Based on the dependence of electric double layers on bulk concentrations, ionic conductance through nanopores at high and low concentrations is governed by the bulk conductance and surface charge density, respectively. Here, through the investigation of ionic conductance inside track-etched single polyethylene terephthalate (PET) nanopores under various concentrations, the surface charge density of PET membranes is extracted as ∼-0.021C/m2 at pH 10 over measurements with 40 PET nanopores. Simulations show that surface roughness can cause underestimation in surface charge density due to the inhibited electroosmotic flow. Then, the averaged pore size and porosity of track-etched multipore PET membranes are characterized by the developed ionic conductance method. Through coupled theoretical predictions in ionic conductance under high and low concentrations, the averaged pore size and porosity of porous membranes can be obtained simultaneously. Our method provides a simple and precise way to characterize the pore size and porosity of multipore membranes, especially for those with sub-100nm pores and low porosities.

Synergizing Multi-Plasticizers for a Starch-Based Edible Film

Synergized multi-plasticizers for a starch-based edible film were developed for food packaging. The most popular edible plasticizers, water, glycerol, and sorbitol were used as modal materials to demonstrate the synergized function of multi-plasticizers. The efficiency, stability, and compatibility of each plasticizer, as well as their synergized functions were investigated based on the characterizations of tensile properties after storing under different humidity conditions and for different times. The relationship between the microstructures of the plasticizers and their performances was studied and established. The results showed that water is an efficient plasticizer but is not stable, which results in it becoming brittle under lower humidity conditions; glycerol has a stronger moisture-retaining and absorption capability, which results in a weaker tensile strength under higher humidity conditions; and sorbitol is an efficient and stable plasticizer but needs to work with water, and its function can be synthesized by mixing it with water and glycerol.

Optical characterizations of Carmine micro-stain thin films and photovoltaic properties of Carbon/Carmine-μ/p-Si/Al for analog–digital conversion applications

Optical characterizations of Carmine micro-stain thin films and photovoltaic properties of Carbon/Carmine-μ/p-Si/Al for analog–digital conversion applications

Analysis of Welding Procedure Specifications for steel line pipe material

This study proposes the welding process steel line pipe material of API5L Grade X52 diameter Ø8 inch SCH80 type, subjected to the good quality of the product by following the Welding Procedure Specifications (WPS). The purpose of welding using WPS is to ensure that the welding process follows the correct stages because the steps are proper. The weld results will be free from defects and safe for line pipes. In order to confirm the WPS quality, the characterisations of macrostructure, microstructure, and mechanical properties were analysed. The welding process results by following the procedure specifications, from macrostructure shown no porosity, and sample without following the welding procedure specifications shown porosity at weld metal position. The tensile test sample following the welding procedure specifications showed high strength and ductility compared with the samples without welding procedure specifications. This phenomenon occurs due to the grain size of the martensitic structure and a little bit of growth compared with a sample without following the welding procedure specifications. Furthermore, the bending test result shows that both samples have no crack at the weld metal position.

In-situ mapping characterization of structure and electrical property of grain boundary in polycrystalline ZnO using nanorobot in SEM

Different from the existing methods of individual characterization of structure or electrical property, a unique approach for in-situ mapping characterization of single grain boundary using nanorobot in SEM is proposed to simultaneously realize the characterization of structure and electrical property in micro-area polycrystalline ZnO. Z-direction height differences constructed by multiple adjacent grains relative to a single target grain can be individually probed by the nanorobot single end tip and correspondingly virtually reconstructed. Electrical impedances complex planes of grain boundaries in-situ detected by nanorobot dual probes can be fitted by equivalent circuits. Experimental results illustrate that in-situ mapping characterization of structure and electrical property of single grain boundary using nanorobot in SEM can be verified. A single grain boundary layer, composed of adjacent multi-grains, seems to be nonlinear and unequal height along the Z direction. Z-direction relative height differences probed by the nanorobot can actually be regarded as the Z-direction projected lengths of surrounding grain boundary interfaces of single target grain. A three dimensional stereogram of single target grain boundary can be virtually reconstructed based on 3D software. It is deduced that schottky barrier existing in grain boundary interface exhibits larger height difference, basically proportional to the thickness of grain boundary in plane X–Y. Furtherly, it can promote an advance in in-situ mapping characterization of structure-property of single/multi micro area in other bulk inorganic polycrystalline bulk materials.

Sparse expanders have negative curvature

We prove that bounded-degree expanders with non-negative Ollivier–Ricci curvature do not exist, thereby solving a long-standing open problem suggested by A. Naor and E. Milman and publicized by Y. Ollivier (2010). In fact, this remains true even if we allow for a vanishing proportion of large degrees, large eigenvalues, and negatively-curved edges. Moreover, the same conclusion applies to the Bakry–Émery curvature condition CD $$(0,\infty )$$ , thereby settling a recent conjecture of D. Cushing, S. Liu and N. Peyerimhoff (2019). To establish those results, we work directly at the level of Benjamini–Schramm limits, and exploit the entropic characterization of the Liouville property on stationary random graphs to show that non-negative curvature and uniform expansion are incompatible “at infinity”. We then transfer this conclusion to finite graphs via local weak convergence. Our approach also shows that the class of finite graphs with non-negative curvature and degrees at most d is hyperfinite, for any fixed $$d\in {\mathbb {N}}$$ .