Triple Defect Research Articles

A novel framework for predicting the burst pressure of energy pipelines with clustered corrosion defects

The accurate prediction of failure pressures in pipelines containing multiple defects is important for assessing the integrity and reliability of corroded pipelines. First, the effect of the remaining defects on the failure pressure of the pipeline containing triple defects was investigated by developing the finite element (FE) model of pipelines containing triple defects. Then, to integrate machine learning method and finite element models to establish a prediction model for the interaction coefficients corresponding to combined corrosion defects. Subsequently, a framework for predicting the burst pressure of pipelines appliable to the scenario of group corrosion defects was proposed by integrating the interacting coefficient and the failure pressure of single defect. Finally, the accuracy of the model was demonstrated by the evaluation indicators and bursting experimental data of corroded pipeline containing cluster defects. The framework is expected to provide a maintenance foundation for the integrity assessment of pipelines with clustered corrosion defects.

Data analysis on the three defect wavelengths of a MoS2-based defective photonic crystal using machine learning

To reduce the dimension of optoelectronic devices, recently, Molybdenum disulfide (MoS2) monolayers with direct bandgap in the visible range are widely used in designing a variety of photonic devices. In these applications, adjustability of the working wavelength and bandwidth with optimum absorption value plays an important role. This work proposes a symmetric defective photonic crystal with three defects containing MoS2 monolayer to achieve triple narrowband defect modes with wavelength adjustability throughout the Photonic Band Gap (PBG) region, 560 to 680 nm. Within one of our designs remarkable FWHM approximately equal to 5 nm with absorption values higher than 90% for the first and third defect modes are achieved. The impacts of varying structural parameters on absorption value and wavelength of defect modes are investigated. Due to the multiplicity of structural parameters which results in data plurality, the optical properties of the structure are also predicted by machine learning techniques to assort the achieved data. Multiple Linear Regression (MLR) modeling is used to predict the absorption and wavelength of defect modes for four datasets based on various permutations of structural variables. The machine learning modeling results are highly accurate due to the obtained R2-score and cross-validation score values higher than 90%.

A promoted charge separation/transfer and surface plasmon resonance effect synergistically enhanced photocatalytic performance in Cu nanoparticles and single-atom Cu supported attapulgite/polymer carbon nitride photocatalyst

The Cu nanoparticles and single-atom Cu-supported attapulgite/polymer carbon nitride (PCN) photocatalyst was successfully synthesized via a calcination process. The C≡N triple bond defect structure was successfully introduced into PCN structure through the composite process of modified attapulgite and PCN, suppressing the recombination of photogenerated electrons, narrowed the bandgap, and improved the efficiency of photocatalytic. The photoluminescence spectra, time-resolved fluorescence spectra, and ultraviolet-visible diffuse reflectance spectra together with theoretical calculation revealed that the doping of single-atom Cu further promoted the separation of photogenerated carriers and reduced the bandgap. The surface plasmon resonance effect produced by Cu nanoparticles and the promoted charge separation and transfer effect of single-atom Cu synergistically enhance the photocatalytic performance, and the degradation rate toward methylene blue dye was 7.7 times higher than that of PCN. Compared with the traditional single-method modified PCN catalyst, the catalyst prepared by this cocktail-like multi-composite strategy has the characteristics of high charge separation efficiency, high catalytic efficiency, and high stability.

Vacancy-based diffusion mechanisms in B2-FeAl: DFT study

This work addresses the ab initio investigations on the possible diffusion mechanisms in B2-FeAl. For this reason, special attention was paid to the dependence of defect formation and diffusion migration energies on the chemical potentials. We compared several diffusion mechanisms that are postulated before and may occur in B2 binary alloys: the triple defect mechanism, next-nearest neighbor vacancy jumps and three kinds of six-jump cycles, which are the [110] six-jump cycle and the bent and straight [100] six-jump cycles. The triple defect mechanism has the highest diffusion activation energy due to its large formation energy and is therefore not a plausible candidate for diffusion in B2-FeAl. We predict that the next-nearest neighbor jump of Fe vacancies and the [110] six-jump cycle are the dominant diffusion mechanisms in B2-FeAl. They also show the best agreement with experimental measurements around the stoichiometric composition. Theoretical findings for B2-FeAl have been compared with B2-NiAl and found no trend. Therefore, the results obtained from one B2 compound cannot be immediately transferred to another one.

L-shape triple defects in a phononic crystal for broadband piezoelectric energy harvesting

This study proposes a phononic crystal (PnC) with triple defects in an L-shape arrangement for broadband piezoelectric energy harvesting (PEH). The incorporation of defects in PnCs has attracted significant attention in PEH fields owing to properties such as energy localization and amplification near the defect. Several studies have been conducted to enhance output electric power of PnC-based PEH systems with single defects. However, it is susceptible to the limitations of narrow bandwidth. Recently, double-defect-incorporated systems have been proposed to widen the PEH bandwidth via defect-band splitting. Nevertheless, the PEH performance rapidly decreases in the frequency range between the split defect bands. The limitations of single- and double-defect-incorporated systems can be resolved by the incorporation of the proposed design concept, called the L-shape triple defects in a PnC. The isolated single defect at the top vertex of the letter ‘L’ compensates for the limitations of double-defect-incorporated systems, whereas the double defects at the bottom vertices compensate for the limitations of the single-defect-incorporated systems. Hence, the proposed design can effectively confine and harvest elastic-wave energy over broadband frequencies while enhancing the application of single and double defects. The effectiveness of the proposed design concept is numerically validated using the finite element method. In the case of a circular hole-type PnC, it is verified that the PnC with L-shape triple defects broadens the bandwidth, and improves the output voltage and electric power compared with those of single- and double-defect-incorporated systems. This study expands the design space of defect-incorporated PnCs and might shed light on other engineering applications of the frequency detector and elastic wave power transfer.

Etching behavior of ground fused silica and light enhancement modulated by surface/subsurface cracks

AbstractThe mechanical defects (scratches/cracks) originated from grinding processing need to be dislodged so that improving the optical performance of fused silica. In this paper, HF‐based (HF represents hydrofluoride acid) etchant was used as a subsequent fabrication for loose‐abrasive ground fused silica, and the surface morphology and characteristics of samples were evaluated, meanwhile, the electric/light field distribution around treated cracks was simulated using the finite difference time domain (FDTD) method. The results show that sufficient material removal amount blunts the cracks to be a series of parabolic‐shaped and smooth craters fused with each other, whose diameter and depth grow as a power function with etched depth. Triple subsurface defect depth should be removed so as to mitigate surface roughness to be ∼2.46 µm and promote transmission from initial 22.55%–54.02%. FDTD simulation results reveal that deep etching alleviates the light intensification factor (LIF) of craters within 1.8 as the diameter‐to‐depth ratio of craters is increased over 10. Moreover, a thickness removal model of ground fused silica involving the cracks distribution characteristics, cracks etching behavior as well as the LIF variation of craters is established, in which the supposed etched depth is determined to promote the manufacturing efficiency and laser damage resistance of the material.

Profiles of Glucose Metabolism in Different Prediabetes Phenotypes, Classified by Fasting Glycemia, 2-Hour OGTT, Glycated Hemoglobin, and 1-Hour OGTT: An IMI DIRECT Study.

Differences in glucose metabolism among categories of prediabetes have not been systematically investigated. In this longitudinal study, participants (N = 2,111) underwent a 2-h 75-g oral glucose tolerance test (OGTT) at baseline and 48 months. HbA1c was also measured. We classified participants as having isolated prediabetes defect (impaired fasting glucose [IFG], impaired glucose tolerance [IGT], or HbA1c indicative of prediabetes [IA1c]), two defects (IFG+IGT, IFG+IA1c, or IGT+IA1c), or all defects (IFG+IGT+IA1c). β-Cell function (BCF) and insulin sensitivity were assessed from OGTT. At baseline, in pooling of participants with isolated defects, they showed impairment in both BCF and insulin sensitivity compared with healthy control subjects. Pooled groups with two or three defects showed progressive further deterioration. Among groups with isolated defect, those with IGT showed lower insulin sensitivity, insulin secretion at reference glucose (ISRr), and insulin secretion potentiation (P < 0.002). Conversely, those with IA1c showed higher insulin sensitivity and ISRr (P < 0.0001). Among groups with two defects, we similarly found differences in both BCF and insulin sensitivity. At 48 months, we found higher type 2 diabetes incidence for progressively increasing number of prediabetes defects (odds ratio >2, P < 0.008). In conclusion, the prediabetes groups showed differences in type/degree of glucometabolic impairment. Compared with the pooled group with isolated defects, those with double or triple defect showed progressive differences in diabetes incidence.

Prevalence of nine genetic defects in Chinese Holstein cattle.

Worldwide use of elite sires has caused inbreeding accumulation and high frequencies of genetic defects in dairy cattle populations. In recent years, several genetic defect genes or haplotypes have been identified in Holstein cattle. A rapid and reliable microfluidic chip with Kompetitive allele‐specific PCR (KASP) assay was developed in our previous study for the detection of heterozygotes at eight genetic defect loci of bovine leukocyte adhesion deficiency (BLAD), Brachyspina syndrome (BS), complex vertebral malformation (CVM), Holstein haplotype 1 (HH1), Holstein haplotype 3 (HH3), Holstein haplotype 4 (HH4), Holstein haplotype 5 (HH5) and haplotype for cholesterol deficiency (HCD). This study aimed to extend that assay to include a newly identified genetic defect of Holstein haplotype 6 (HH6) and to estimate the frequencies of carriers for each of the nine genetic defects in six Chinese Holstein herds. Of the 1633 cows, carrier frequencies of the genetic defects were 6.92%, 5.76%, 4.46%, 4.30%, 3.62%, 2.94%, 1.86% and 0.37% for HH1, HH3, CVM, HH5, HCD, BS, HH6 and BLAD, respectively. No carrier was found for HH4. Notably, 27.43% of cows carried at least one genetic defect, while 2.27% and 0.12% of cows carried double and triple genetic defect alleles, respectively. The existence of genetic defects calls for routine molecular testing and effective management of genetic defects by avoiding carrier‐to‐carrier mating in production herds and eliminating or at least reducing the frequency of the defective alleles through marker‐assisted selection in breeding herds.

Double-humped phonon resonance in doubly resonant vibration systems: Phonon metamaterials analogy with doubly resonant electromagnetic structures

Phononic metamaterial which consists of two (or several) nanolayers separated by a planar defect of atomic-scale thickness is studied, under the assumption that the two-channel phonon interference mechanism of the transverse (cross-plane) heat flux control is dominant at high temperatures. An analytically exactly solvable discrete three-dimensional (3D) model of the multilayer interface between two semi-infinite bcc-lattice crystals is used to simulate phononic metamirror, metafilter, and meta-absorber. Two options of the general model in which two-path phonon interference reveals itself as double-humped resonance in the interface phonon absorption at weak dissipation or as total phonon transmission and total phonon reflection in the lossless limit are considered. An analogy is discussed between doubly resonant dissipative vibration systems and earlier investigated doubly resonant electromagnetic structure exhibiting both types of behavior: induced transparency and superscattering. It is shown that triple-peaked absorption resonance may arise from superposition of two-path phonon interference and Fabry-P\'erot-type interference in the system with triple defect layer. The existence conditions of double-peaked and triple-peaked resonances as well as total interface absorption are analyzed in terms of nondissipative phonon scattering properties and dissipative parameters. Also additional peculiarities relevant to the thermal interface resistance problem are described. The study provides insight into heat management in phononic nanostructures and metamaterials like metamirrors, metafilters, and meta-absorbers.

Diffusion, defects and understanding the growth of a multicomponent interdiffusion zone between Pt-modified B2 NiAl bond coat and single crystal superalloy

Composition-dependent diffusion coefficients are determined in B2-Ni(CoPt)Al system following the pseudo-binary and pseudo-ternary diffusion couple methods, which would not be possible otherwise in a quaternary inhomogeneous material fulfilling the conditions to solve the equations developed based on the Onsager formalism. The end-member compositions to produce ideal/near-ideal diffusion profiles are chosen based on thermodynamic details. The pseudo-binary interdiffusion coefficients of Ni and Al decrease in the presence of Co but increase in the presence of Pt. The pseudo-ternary interdiffusion coefficients indicate that the main interdiffusion coefficients increase significantly in the presence of Pt. Marginal changes of the cross interdiffusion coefficients substantiate a minor change of the diffusional interactions between the components. The thermodynamic driving forces show opposite trends with respect to composition as compared to the changes of the interdiffusion coefficients advocating a dominating role of the Pt(Co)-induced modifications of point defect concentrations. DFT-based calculations revealed that Pt alloying increases the Ni vacancy concentration and decreases the activation energy for the triple defect diffusion mechanism. These findings explain the increase in the thickness of the interdiffusion zone between the B2-Ni(Pt)Al bond coat and the single crystal superalloy René N5 because of Pt addition. Furthermore, the EPMA and TEM analyses reveal the growth of refractory elements-enriched precipitates.

A case report of triple neural tube defect: revisiting the multisite closure theory

BackgroundTriple neural tube defects are rare. To the author’s knowledge, there are only four reported cases available in the literature up to date. Controversies exist with regards to the development of neural tube defects. We revisit the multisite closure theory and try to explain the mechanism of neural tube defects in our case.Case presentationWe report a case of one-month-old baby boy who presented to us with three distinct neural tube defects. He had occipital and cervical encephaloceles along with thoracolumbar myelomeningocele accompanied by syrinx and mild hydrocephalus. All the three defects were surgically corrected with good neurological outcome.ConclusionIn the multisite model of human neural tube closure, there are only two fusion sites and two neuropores unlike in mouse. This can explain the origin of open neural tube defects including anencephaly and myelomeningocele (as in our case) but cannot account for the development of encephalocele, which appears to be a post neurulation defect.

The role of open-volume defects in the annihilation of antisites in a B2-ordered alloy

The atomic arrangement in certain ordered alloys, such as B2–Fe60Al40 determines intrinsic material properties for instance, the saturation magnetization. Here we have investigated the influence of open-volume defects on the atomic ordering process at elevated temperatures in Fe60Al40 thin films. A dependence of the ordering process on the type and concentration of defects is observed by positron annihilation spectroscopy combined with ab-initio calculations. Comparing the lifetimes of positrons in the alloy for different annealing and irradiation treatments reveals the role of mono-vacancies, triple defects as well as large vacancy clusters: The rate of atomic ordering to the ordered B2 state is increased in the presence of mono-vacancies whereas triple defects and vacancy complexes decrease the ordering rate. Furthermore, an agglomeration of vacancies during annealing to di-vacancies and larger vacancy clusters is observed. The distribution of open-volume defects can be modified in such a way as to control the thermal stability via ion-irradiation and thermal pre-treatments.

Revealing the failure mechanism and designing protection approach for MoS2 in humid environment by first-principles investigation

Abstract The moist circumstance (e.g., O2 and H2O molecule) is one of the critical factors affecting the application of MoS2, which lead to MoS2 failure. Fortunately, metal-atoms doping MoS2 is commonly used to decrease damage of MoS2 by O2 or H2O molecule. To understand and explore the microscopic mechanism of MoS2 failure, the interaction of O2, H2O molecule with defect-free, defected MoS2 is calculated using first-principles method. It could be found that the failure of MoS2 results mainly from the defects, which make the exposed Mo atoms more active and easy to react with O2 or H2O molecule. Therein to, S-vacancy defect of MoS2 (MoS2-VS1 species) is the reaction outset point of O2 environment, and triple vacancy defect of MoS2 (MoS2-VS2+Mo species) is that of H2O environment. Based on this failure mechanism, the typical Ti or Pb elementals doped MoS2 are studied, the calculation results indicate that Ti or Pb doping elements can retard effectively the failure of MoS2 in humid environment through reacting preferentially with or repulsing to O2 or H2O molecules, and even restraining the diffusion of H atom dissociated from H2O molecule. All of these will be helpful for the design, synthesis, and application of related transition metal dichalcogenides.

Vacancy effects on the mechanical behavior of B2-FeAl intermetallics

The present work addresses the impact of quenched-in thermal vacancies on the mechanical properties of B2 iron aluminides. For this reason different binary Fe-Al alloys with different histories of heat treatment were indented at room temperature. The contributions of mono- and bi-vacancies in addition to triple defects on the elastic, plastic and elastic-plastic transition were evaluated using nanoindentation technique. In the samples containing bi-vacancies, the increase of the hardness was much more pronounced compared to the mono-vacancies.

Diffusion in B2 NiAl and FeAl Intermetallics and Their Alloys

Both FeAl and NiAl with B2 crystal structure are envisaged for their usage in high temperature applications and hence, availability of diffusion data in these intermetallics is crucial in designing their alloys and processes as well as deciding their in-service performance. A comprehensive overview of diffusion data available in B2 FeAl and NiAl and their alloys is provided in this article. Nearest neighbor vacancy jumps in B2 intermetallic lead to a local disorder in the lattice and hence it is not necessarily the unit step of diffusion in these structures. Several mechanisms of diffusion proposed in the literature are discussed including nearest neighbor jumps, next nearest neighbor jumps, six-jump vacancy cycle, triple defect and antisite bridge. Relevance of these mechanisms in FeAl and NiAl is discussed. An overview is given on the self-and solute diffusion and interdiffusion data available in both binary FeAl and NiAl. Due to wide solubility range of both FeAl and NiAl as well as their alloying requirements for improved properties, it becomes pertinent to study the multicomponent diffusion in the alloys based on these B2 itnermetallics. Hence, in the latter part of the article, various methods used for determining multicomponent diffusion data are reviewed. A detail overview is also provided on the diffusion studies available in literature on ternary alloys based on FeAl and NiAl with an emphasis on highlighting the diffusional interactions observed in these systems.

A first-principles study on the origin of magnetism induced by intrinsic defects in monolayer SnS2

The effect of intrinsic defects on the structural, electronic and magnetic properties of monolayer SnS2 has been studied using density functional theory. Among the possible intrinsic defects, S vacancy is the most energetically favorable intrinsic defect under the Sn-rich condition, while S-on-Sn anti-site defect is most likely to form under the S-rich condition. Besides, S-on-Sn anti-site defect can realize p-type semiconductor behavior. Additionally, Sn vacancy, Sn-on-S anti-site and S adsorption on the top of S atom from the upper triple layer defects can induce magnetism, which originates mainly from the nearest-neighbor S atoms close to the Sn vacancy, Sn substitutional atom and S adatom, respectively. Moreover, the room temperature ferromagnetism is possible to be realized in monolayer SnS2 with S adsorption on the top of S atom from the upper triple layer defects. These predictions give a new path to explore monolayer SnS2-based magnetic nanomaterials.

Surface Fraction Dependence of Contact Angles Induced by Kinks in the Triple Line.

On periodic superhydrophobic surfaces the receding contact angle often scales with the surface fraction, as expected from a simple rule of mixture, the Cassie relation. However, it has been argued that energy averaging breaks down owing to line pinning, and that line fraction scaling should apply instead. From experiments and simulations we show that proper inclusion of triple line defects introduce surface fraction scaling in the line depinning threshold. In contrast to the Cassie relation and in agreement with the data, this dependence is strongly nonlinear due to triple line elasticity.

A dual‐band compact printed monopole antenna using multiple rectangle‐shaped defected ground structures and cross‐shaped feed line

ABSTRACTA compact printed monopole antenna with dual‐band operation at 1.8 GHz (GSM Band) and 5.2 GHz (Wi‐Fi Band) is presented. The antenna consists of a modified U‐shaped radiating patch with a triple rectangular defect in the ground plane. The antenna is fed by a cross‐shaped feed line, which helps in realizing the dual‐band operation. The antenna has been designed using RO4350 substrate. The design size achieved is 19 × 28 mm2. An impedance bandwidth of about 32% at 1.8 GHz and about 29% at 5.2 GHz for 10 dB return loss has been achieved. A size reduction of about 12% in comparison with a similar antenna without defected ground structures has been achieved. The proposed antenna has been fabricated and tested, and a good agreement between simulated and measured results is seen. Acceptable E‐plane and H‐plane radiation patterns have been observed through simulations, and a peak antenna gain of about 2.8 dBi has been achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1810–1813, 2015

Orbit based procedure for doublets of scalar fields and the emergence of triple kinks and other defects

In this work we offer an approach to enlarge the number of exactly solvable models with two real scalar fields in (1+1)D. We build some new two-field models, and obtain their exact orbits and exact or numerical field configurations. It is noteworthy that a model presenting triple-kinks and double-flat-top lumps is among those new models.

Semigrand Canonical and Kinetic Monte Carlo simulations of binary B2-ordered nano-films with triple defects

Equilibrium atomic configurations and the kinetics of “order–order” and surface segregation processes in B2-ordering stoichiometric A-50 at.%B binary thin films are investigated by means of Semigrand Canonical Monte Carlo (SGCMC) and Kinetic Monte Carlo (KMC) simulations. The (100)-oriented films are modeled with an Ising-type Hamiltonian with previously evaluated pair-interaction energy parameters yielding the effect of “triple-defect disordering”. The SGCMC simulations provide equilibrium vacancy concentration and atomic configuration in the films with B-atom termination of both free surfaces achieved at high temperatures by the generation of an antiphase boundary. Despite strong vacancy surface segregation, the thermodynamic activation energy for their formation inside the films is the same as in the bulk material. KMC simulations implemented with the SGCMC-determined equilibrium vacancy concentration reveal very slow relaxation of the films towards equilibrium configuration. The B-termination of the (100) free surfaces is produced by A-atom diffusion inwards into the films mediated by vacancies segregating on surfaces.