Integral Properties Research Articles

Investigation of Roller Burnishing Process on 20MnCr5 Steel

Burnishing is a mechanical treatment for the quality improvement of rotating components. This work aims to investigate the effect of a burnishing process on the surface integrity properties of 20MnCr5 steel and the resulting performance of this alloy due to the burnished-induced surface properties through a systematic experimental study that was conducted to examine the influence of process parameters. An empirical model involving the number of passes, speed, and feed is developed for out-of-roundness prediction. The results of the Taguchi method are compared with experimental results. It was found that the out-of-roundness obtained is 0.001 microns.

Surface integrity and mechanical properties of small elements fabricated through LPBF and post-processed with heat treatment and abrasive machining

AbstractThe present research analyzes the impact of heat treatment atmosphere followed by finishing surface machining of small elements of Inconel 939 fabricated through laser powder bed fusion (LPBF). The analysis involved annealing in two gas mediums, solution treatment, and aging to achieve the desired microstructure and mechanical properties. The finishing surface was performed using various variants of abrasive machining. A more than fivefold reduction in the average roughness height Ra from 5.6 µm to 1.15 µm was achieved using metal balls as an abrasive, which was required for further processing. Residual stress tests have shown that due to heat and abrasive treatment, tensile stresses change into compressive ones. After printing, samples are characterized by tensile residual stresses on the surface (+ 428 MPa), while after heat treatment, compressive stresses occur (− 179 MPa). Abrasive machining with metal balls increases the value of compressive stresses to − 464 MPa. In addition, the impact of post-processing on the microstructure of Inconel 939 was discussed in terms of mechanical properties. The yield strength of 1184 MPa and elongation values of 19.3% were obtained for samples after HT in an argon atmosphere and abrasive machining with a ceramics roller. These studies provide valuable new information on the effective heat treatment and optimization of the finishing machining of Inconel 939, especially in achieving the desired surface roughness, microstructure, and mechanical properties for aerospace applications.

Matching combination of amorphous ionic hydrogel with elastic fabric enables integrated properties for wearable sensing

The combination of hydrogels and fabrics opens up significant opportunities for flexible materials, particularly in biomedicine and wearable technology. However, the weak interface caused by insufficient interactions between the different phases and the substantial modulus mismatch limit their broader application. In this research, flexible and amorphous polyvinyl alcohol (PVA) hydrogels were integrated with polar and elastic fabrics to create multifunctional composites via in-situ freeze-thawing technology. First, by incorporating antifreeze inorganic salts into the precursor solution, we effectively suppressed ice crystal growth during the cooling process, promoting a uniform and loosely aligned PVA chain structure. This led to the formation of an amorphous crosslinked network while simultaneously releasing free hydroxyl groups. These hydroxyl groups facilitate the formation of robust interfaces within the composite. In addition, an elastic fabric composed of a polyester-polyurethane fiber blend was selected. The polyester fibers, rich in carbonyl groups along their polymer chains, form strong hydrogen bonds with the free hydroxyl groups from the PVA hydrogel, creating a highly resilient interface. The polyurethane fibers contribute to a lower Young's modulus, as well as excellent elasticity and ductility, reducing the fabric's inherent stiffness and mitigating fiber pull-out failure. Further, the incorporation of CaCl2 not only created an environment rich in free ions, but also provided the amorphous structure with increasing spacing between adjacent polymer chains, facilitating the transportation of ions. Therefore, the composite exhibits adept sensing capabilities for intricate human body movements, fostering auspicious prospects in smart sensor applications.

On a class of oscillatory integrals and their application to the time dependent Schrödinger equation

In this paper a class of oscillatory integrals is interpreted as a limit of Lebesgue integrals with Gaussian regularizers. The convergence of the regularized integrals is shown with an improved version of iterative integration by parts that generates additional decaying factors and hence leads to better integrability properties. The general abstract results are then applied to the Cauchy problem for the one dimensional time dependent Schrödinger equation, where the solution is expressed for Cn-regular initial conditions with polynomial growth at infinity via the Green's function as an oscillatory integral.

The Riemann-Liouville fractional integral in Bochner-Lebesgue spaces III

In this manuscript, we examine the continuity properties of the Riemann-Liouville fractional integral for order α=1/p, where p>1, mapping from Lp(t0,t1;X) to the Banach space BMO(t0,t1;X)∩K(p−1)/p(t0,t1;X). This improvement, refines a result by Hardy-Littlewood. To achieve this, we study properties between spaces BMO(t0,t1;X) and K(p−1)/p(t0,t1;X). Additionally, we obtained the boundedness of the fractional integral of order α≥1 from L1(t0,t1;X) into the Riemann-Liouville fractional Sobolev space WRLs,p(t0,t1;X).

Silane-modified layered double hydroxides with europium sensor for singlet oxygen detection

A silane-modified layered double hydroxide (LDH) hybrid with a covalently coupled europium complex for aqueous singlet oxygen (1O2) detection is presented. A Mg/AL-LDH is modified with two alkoxysilanes simultaneously to increase its covalent linkability (using -SH or -NH2 groups) and to improve its dispersibility in water (using -N+(CH3)3 groups). The europium complex – here acting as the 1O2 probe – is coupled to the –SH or -NH2 - modified LDH employing epoxyphenanthroline (5,6-Epoxy-5,6-dihydro-[1,10]phenanthroline, “ephen”), which is acting as an ancillary ligand to the europium via its hetero-aromatic N-atoms on one hand and allows the covalent linkage of its epoxy-group to the modified LDH on the other hand. In this manner, the silane chains keep the europium complex away from the chemically active LDH surface, hence maintaining its structural integrity and photophysical properties. The result is a water-dispersible probe with a remarkable response to 1O2. This is signaled by the significant increase in the characteristic Eu3+ emission at 613 nm resulting in up to a 27-fold increase in emission intensity on exposure to 1O2 having a decay time of 380 μs. The resulting Eu-LDH hybrid is applicable for heterogeneous aqueous 1O2 detection; its long decay time, useful in time-gated measurements, in conjunction with the biocompatibility of LDH makes it particularly suitable for biological matrices, where 1O2 needs to be monitored.

Enhanced strength-ductility synergy in a Ni–W–Co–Ta medium-heavy alloy via cryogenic supersonic fine particle bombardment

This study explores the influence of cryogenic supersonic fine particle bombardment (CSFPB) on a Ni–W–Co–Ta medium heavy alloy (MHA), and focus on the effect of gas pressure and impact time on the surface integrity, microstructural evolution, and mechanical properties of the MHA. CSFPB treatment creates a gradient structure, including surface layer with nanograins down to 9.0 nm due to severe plastic deformation, subsurface layer with high density dislocation structures and deformation twins due to weakened impact energy, and undeformed matrix. A key advantage of CSFPB is seen to be the cryogenic environment, which promotes superior surface integrity by reduced roughness. As the impact duration and gas pressure increase, the depth of deformation layer, surface hardness and strength of the MHA progressively rise. The optimal combination of strength and ductility is achieved at a gas pressure of 1.0 MPa for a duration of 90 s. This setting results in a maximum ultimate tensile strength of 1351 MPa and yield strength 796 MPa, with uncompromising elongation. However, excessively long treatment durations or high gas pressures can lead to the formation of surface microcracks, ultimately reducing the MHA's strength. Therefore, CSFPB offers the benefit of improved surface integrity through the cryogenic environment while maintaining a desirable balance between enhanced strength and ductility.

A Comparative View of Becker, Lomnitz, and Lambert Linear Viscoelastic Models

We compare the classical viscoelastic models due to Becker and Lomnitz with respect to a recent viscoelastic model based on the Lambert W function. We take advantage of this comparison to derive new analytical expressions for the relaxation spectrum in the Becker and Lomnitz models, as well as novel integral representations for the retardation and relaxation spectra in the Lambert model. In order to derive these analytical expressions, we have used the analytical properties of the exponential integral and the Lambert W function, as well as the Titchmarsh’s inversion formula of the Stieltjes transform. In addition, we prove some interesting inequalities by comparing the different models considered, as well as the non-negativity of the retardation and relaxation spectral functions. This means that the complete monotonicity of the rate of creep and the relaxation functions is satisfied, as required by the classical theory of linear viscoelasticity.

Recovering chemical bimodalities in observed edge-on stellar disks: Insights from AURIGA simulations

The well-known bimodal distribution of Milky Way disk stars in the [α/Fe]–metallicity plane is often used to define thick and thin disks. In external edge-on galaxies, there have been attempts to identify this type of bimodality using integral field spectroscopy (IFS) data. However, for unresolved stellar populations, observations only contain integrated information, making these studies challenging. We assessed the ability to recover chemical bimodalities in IFS observations of edge-on galaxies, using 24 Milky Way-mass galaxies from the AURIGA zoom-in cosmological simulations. We first analyzed the distribution of single stellar particles in the [Mg/Fe]–[Fe/H] plane, finding that bimodality is frequent but not ubiquitous and often unclear. Then we produced mock IFS [Mg/Fe] and [Fe/H] maps of galaxies seen edge on, and considered integrated stellar-population properties (projected and spatially binned). We investigated how the distribution of stars in the [Mg/Fe]–[Fe/H] plane is affected by edge-on projection and spatial binning. Bimodality is preserved, while distributions change their shapes. Naturally, broad distributions of individual star particles are narrowed into smaller [Mg/Fe] and [Fe/H] ranges for spatial bins. We observe continuous distributions from high [Mg/Fe] and low [Fe/H], to lower [Mg/Fe] values and higher [Fe/H]. Despite being continuous, these distributions are bimodal in most cases. The overlap in [Fe/H] is small, and different [Mg/Fe] components show up as peaks instead of sequences (even when the latter are present for individual particles). The larger the spatial bins, the narrower the [Mg/Fe]–[Fe/H] distribution. This narrowing helps amplify the density of different [Mg/Fe] peaks, often leading to a clearer bimodality in mock IFS observations than for original star particles. We also assessed the correspondence of chemical bimodalities with the distinction between geometric thick and thin disks. Their individual particles have different distributions, but mostly overlap in [Mg/Fe] and [Fe/H]. However, integrated properties of geometric thick and thin disks in mock maps do mostly segregate into different regions of the [Mg/Fe]–[Fe/H] plane. In bimodal distributions, they correspond to the two distinct peaks. Our results show that this approach can be used for bimodality studies in future IFS observations of edge-on external galaxies.

The Application of Definite Integral In Different Aspects

A definite integral is a form of a calculation of area beneath of function, using infinitesimal silver or stripes of the region. Different from indefinite integral which representing a function, definite integral is a specific value. The value of a definite integral only depends on the interval of this integral, which means for the same function and interval, the result won’t change with different variables. Integrals may represent the area of a region, the accumulated value of a function changing over time, or the quantity of an item given its density. This method can be used to solve many problems in different fields. This paper will explore some applications of definite integral. This article first introduces the applications of definite integrals in geometry, and then studies their applications in physics, such as variable force work and pumping work. Finally, how to use the properties of definite integrals to solve limit problems will be further studied.

Biocompatible Zn-Phthalocyanine/Gelatin Nanofiber Membrane for Antibacterial Therapy.

In this study, the fabrication and characterization of Zn-phthalocyanine/gelatin nanofibrous membranes is reported using the electrospinning technique. The membranes exhibit a homogeneous distribution of Zn-phthalocyanine within the gelatin matrix, maintaining the structural integrity and photosensitizing properties of the phthalocyanine. Scanning electron microscopy revealed that the electrospun fibers possess diameters ranging results as 100-300, 200-700, and 300-800nm for Gel, ZnPc/Gel 1, and ZnPc/Gel 2, respectively. The addition of ZnPc does not decrease the hydrophilicity of the Gel membrane. The nanofibrous membranes showed good cytocompatibility, as indicated by the high viability of Vero cells exposed to membrane extracts. Furthermore, these composites supported cell adhesion and proliferation on their surfaces. The two Zn-phthalocyanine/gelatin nanofiber formulations exhibited significant antimicrobial activity toward Escherichia Coli (E. Coli) and Staphylococcus Aureus (S. Aureus) under visible light illumination, achieving reductions of 3.4 log10 and 3.6 log10 CFUmL-1 for E. coli, and 3.9 log10 and 4.1 log10 CFUmL-1 for S. aureus. These results demonstrate the potential of Zn-phthalocyanine/gelatin nanofibrous membranes as effective agents in antibacterial photodynamic therapy, providing a promising solution to control bacterial infections and antibiotic resistance.

Numerical simulation of the two-dimensional fractional Schrödinger equation for describing the quantum dynamics on a comb with the absorbing boundary conditions

This paper mainly contributes to investigating a distinctive fractional Schrödinger equation (FSE) for describing the quantum dynamics on a comb. The special characteristic of the comb is that the diffusion versus the x-direction only occurs on the x-axis. We replace the infinite boundary with the absorbing boundary conditions (ABCs), which can be obtained using the Laplace transform. We utilize the integration property to deal with the singularity function in the FSE and propose the finite difference method. The stability and convergence of this scheme are investigated. The L1 scheme to discretize the Caputo fractional derivative needs a particularly expensive computational and storage cost. To increase the calculation speed, a fast algorithm is used to improve the operation efficiency. By introducing a source term, the exact solution and the numerical solution are compared. The comparison of the CPU time for the L1 scheme and fast scheme is given. The comparison between the FSE on a comb and the classical one is also analyzed and discussed. The transport process versus the x-axis and the y-axis with various parameters are shown. Finally, the mean square displacement (MSD) is investigated. We find that the solution with the ABCs has a better agreement with the exact expression compared to the solution with truncated zero boundary conditions.

Electricallymodified bacterial cellulose tailored with plant based green materials for infected wound healing applications

Effective treatment of infected wounds remains a challenge due to the rise of antibiotic-resistant microorganisms. The development of advanced materials with strong antimicrobial properties is necessary to address this issue. In this study, a unique composite of electrically modified bacterial cellulose (EBC) with allantoin (ABC) and zein was developed by dipping diffusion method. Morphological structural analysis revealed a uniform distribution of zein and aligned fibers, confirming the synthesis of the ABC-Zein composite. The formation of ABC-Zein was further confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR), which displayed additional peaks corresponding to EBC, indicating the incorporation of zein into ABC. X-ray diffraction (XRD) analysis of ABC-Zein demonstrated a similar crystalline structure with EBC. The ABC-Zein showed mechanical integrity (tensile strength: 1.15 ± 0.21 MPa), thermal stability (degradation temperature: 290 °C), porous structure (porosity: 40.23 ± 0.21 %), and hydrophilic (water contact angle: 53.3 ± 5.3°) properties. Furthermore, the antimicrobial agent terpinen-4-ol (T4O), derived from tea tree oil, was incorporated into the ABC-Zein composite. Biological studies confirmed the antimicrobial efficacy (Staphylococcus aureus inhibition: 88.5 ± 7.19 %) and biocompatible (cell viability: 84.95 ± 5.6 %, hemolysis: 4.479 ± 0.39 %) nature of the T4O-ABC-Zein composite. The combined effects of the aligned fiber structure, zein protein, and antimicrobial T4O significantly enhanced infected wound healing by day 7, promoting inflammatory response, granular tissue formation, cell proliferation, and angiogenesis. By day 14, T4O-ABC-Zein facilitated complete wound healing, with reepithelization, collagen I deposition, and downregulation of CD 31, Ki67, and α-SMA. Overall, the innovative T4O-ABC-Zein composite, with an aligned fiber structure, improved biocompatibility, and antimicrobial properties, holds significant potential for the treatment of infected wounds.

A new variant of the electromagnetic field theory of consciousness: approaches to empirical confirmation.

There are various electromagnetic (EM) field theories of consciousness. They postulate an epineural EM field which, due to its binding properties, unifies the different neuronal information differences originating from various sensory and cognitive processes. Only through a real physical integration in space within this field could phenomenal consciousness arise. This would solve the binding problem mentioned in the philosophy of mind. On closer inspection, the electromagnetic interaction not only provides an explanation for the integrative property of the EM field, but also for the necessary differentiating contrasts of information. This article will take a closer look at the physical properties of a postulated EM field. It will also show how the problem of qualia in connection with emergentism could be solved by a new variant of EM field theory. If it can be clearly demonstrated that the postulated epineural EM field plays a decisive role in the origin of consciousness in addition to neuronal "wired" information processing, this also leaves less room for metaphysical assumptions that attempt to solve the binding problem. In experiments to prove the postulated epineural EM field by means of external electromagnetic manipulations, it can never be ruled out that these also have a direct effect on the "wired" neuronal signal processing. Therefore, on the way to proving the EM field theory of consciousness, an experimental method is needed that must ensure that external manipulations only affect the extensions of the EM field without directly influencing the neuronal network. A method will be discussed here that works with the shielding of EM fields instead of external electromagnetic stimuli.

Effect of laser shock peening on the surface integrity and fretting fatigue properties of high-strength titanium alloy TC21

High-strength titanium alloy TC21 is often used to make aircraft load-bearing components in the aviation field. However, due to vibration, load-bearing components often suffer from fretting fatigue (FF), which greatly reduces their actual service life. Nowadays, laser shock peening (LSP) is being recognized as an effective strengthening process for many materials. Therefore, in this study, the effectiveness of LSP on the strengthening of high-strength titanium alloy TC21 is studied, in terms of surface integrity and FF properties. TC21 fretting specimens and tests are designed. Before fretting tests, the specimens are processed by LSP with varying laser pulse energies, number of shocks and overlap rate, and their surface integrity and FF properties are analyzed. It is found that the greater the laser pulse energy and number of shocks, the higher the surface hardness and compressive residual stress, the more the grain refinement, the greater the improvement in FF life. Under 32J-50%-T1, the FF life is improved by 191.3% compared with BM. But the overlap rate has little effect on surface integrity and FF life. Meanwhile, there forms amorphous structures, which tended to be transformed into nanograins during fretting process. This transformation is helpful for prolonging FF life due to its action of energy absorption. This study reveals the strengthening mechanism of LSP on TC21 and its effect on the FF properties of TC21 specimens.

Solitonic Analysis of the Newly Introduced Three-Dimensional Nonlinear Dynamical Equations in Fluid Mediums

The emergence of higher-dimensional evolution equations in dissimilar scientific arenas has been on the rise recently with a vast concentration in optical fiber communications, shallow water waves, plasma physics, and fluid dynamics. Therefore, the present study deploys certain improved analytical methods to perform a solitonic analysis of the newly introduced three-dimensional nonlinear dynamical equations (all within the current year, 2024), which comprise the new (3 + 1) Kairat-II nonlinear equation, the latest (3 + 1) Kairat-X nonlinear equation, the new (3 + 1) Boussinesq type nonlinear equation, and the new (3 + 1) generalized nonlinear Korteweg–de Vries equation. Certainly, a solitonic analysis, or rather, the admittance of diverse solitonic solutions by these new models of interest, will greatly augment the findings at hand, which mainly deliberate on the satisfaction of the Painleve integrability property and the existence of solitonic structures using the classical Hirota method. Lastly, this study is relevant to contemporary research in many nonlinear scientific fields, like hyper-elasticity, material science, optical fibers, optics, and propagation of waves in nonlinear media, thereby unearthing several concealed features.

Effect of multidirectional forging on grain structure and mechanical properties of hypereutectic Al–20%Si alloys with added refiners and modifiers

ABSTRACT The present work is focused on the multidirectional forging (MDF) of Al–20 wt-% Si alloys with the addition of refiners and modifiers. The MDF process was performed at 200°C with a cumulative strain of 0.63. Microstructural characterization and mechanical performance were evaluated on the Al–20Si, Al–20Si–4.5Cu, Al–20Si–4.5Cu–1(Al–Ti–B), Al–20Si–4.5Cu–1(Al–Ti–B)–10(Al–Sr). The microstructure analysis revealed significant changes in the eutectic and primary phase refinement. The micro-Vickers hardness confirmed that the MDF process resulted in increased hardness (125 ± 1.9 VHN) compared to the homogenized samples (96 ± 2.7 VHN). Tensile test results showed that with the accumulation of strain, ultimate tensile strength increased to 435 MPa from 302 MPa with reduction in the percentage of elongation from 7.8 to 5.6. The grains were more uniformly distributed with addition of modifiers, and refiners further reduced the nucleation number of eutectic grains. The wear study demonstrated that the wear resistance is more in the Al–Si-Cu-Sr sample due to the increased level of hardness. The combination of multidirectional forging techniques with judicious incorporation of refiners and modifiers engenders a synergistic enhancement of microstructural integrity, hardness profiles, and wear-resistant properties in hypereutectic Al-20Si alloys.

Ultrastable and Low-Threshold Two-Photon-Pumped Amplified Spontaneous Emission from CsPbBr3/Ag Hybrid Microcavity.

Halide perovskite materials have garnered significant research attention due to their remarkable performance in both photoharvesting photovoltaics and photoemission applications. Recently, self-assembled CsPbBr3 superstructures (SSs) have been demonstrated to be promising lasing materials. In this study, we report the ultrastable two-photon-pumped amplified stimulated emission from a CsPbBr3 SS/Ag hybrid microcavity with a low threshold of 0.8 mJ/cm2 at room temperature. The experimental results combined with numerical simulations show that the CsPbBr3 SS exhibits a significant enhancement in the electromagnetic properties in the hybrid microcavity on Ag film, leading to the uniform spatial temperature distribution under the irradiation of a pulsed laser, which is conducive to facilitate the recrystallization process of the QDs and improve their structural integrity and optical properties. This study provides a new idea for the application of CsPbBr3/Ag hybrid microcavity in photonic devices, demonstrating its potential in efficient optical amplification and upconversion lasers.

Thermodynamic modeling of liquid binary alloys of the Al–Er system

The paper presents the results of a study of the thermochemical properties of the Al–Er system. The thermodynamic characteristics were evaluated (△fH0298, S0298, (H0298−H00), Cp(T) and Cp(liq)) for the intermetallic compounds Al3Er, Al2Er, AlEr, Al2Er3, AlEr2. The values of△fH0298 calculated based on the semiempirical Miedema model adapted for the group of Al–REM alloys were taken for calculations and amounted to –47.7, –58.4, –63, –55.2, –46.8 kJ/mol∙at, respectively. The mixing characteristics of liquid alloys of this system were evaluated by Terra software package for modeling the equilibrium states of heterogeneous inorganic systems with an extensive database of properties of individual substances. The model of ideal solutions of interaction products was used as a computational model. Modeling of equilibrium composition and properties of melts was carried out in the temperature range of 1900–2100 K, in an argon atmosphere at a total pressure of 0.1 MPa in the system. Comparison of the obtained results with the simulation results in the approximation of an ideal solution, allowed us to determine the excess integral thermodynamic properties of liquid alloys (Gibbs energy, enthalpy, and entropy). It is shown that in the studied temperature range, with an increase of temperature, there is a natural, though not significant, decrease in the values of these parameters by absolute value. It is established that the formation of liquid alloys of the Al–Er system is accompanied by significant heat release: the value of the integral enthalpy of mixing at a temperature T = 2100 K is –58.9 kJ/ mol∙at. When comparing the thermochemical properties of the Al–Er system with the binary systems Al–Y and Al–Sc studied by the same methods, it is shown that all energy curves pass through the extremum at XSc,Y,Er ≈ 0.5. The strongest interaction of the components is observed in the Al–Y system, (ΔHmix = –58.9 kJ/mol∙at), which is close enough to the maximum modulo value of the enthalpy of mixing in the Al–Er system. The weakest interaction is observed in the Al–Sc system (ΔHmix = –44.8 kJ/mol·at). The results obtained in this work provide a theoretical basis for further experimental study of erbium–containing aluminum alloys.

Specifying and Verifying Information Flow Control in SELinux Configurations

Security Enhanced Linux (SELinux) is a security architecture for Linux implementing Mandatory Access Control. It has been used in numerous security-critical contexts ranging from servers to mobile devices. However, its application is challenging as SELinux security policies are difficult to write, understand, and maintain. Recently, the intermediate language CIL was introduced to foster the development of high-level policy languages and to write structured configurations. Despite CIL’s high level features, CIL configurations are hard to understand as different constructs interact in non-trivial ways. Moreover, there is no mechanism to ensure that a given configuration obeys desired information flow policies. To remedy this, we enrich CIL with a formal semantics, and we propose IFCIL, a backward compatible extension of CIL for specifying fine-grained information flow requirements. Using IFCIL, administrators can express confidentiality, integrity, and non-interference properties. We also provide a tool to statically verify these requirements and we experimentally assess it on ten real-world policies.