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Laser powder bed fusion (LPBF) is a cost-effective and relatively fast additive manufacturing (AM) technique, utilizing a laser source to selectively melt metallic powder and produce objects with intricate geometries. Nevertheless, establishing effective real-time monitoring methods for this process remains a notable challenge. The interaction between the laser and metallic powder leads to the ejection of particles, referred to as spatter, with varying sizes, velocities, trajectories, and spatial distributions. Literature indicates that the behavior of these spatters can serve as a potential indicator of defect generation during the AM process. This study investigates the potential for employing a well-established electromagnetic (EM) model to monitor the scattering properties of spatters. This approach serves as a potential tool to identify variations in spattering behavior that might be associated with defect generation during the process. The study explores how parameters, such as spatial distribution and the number of particles (in a given volume), impact the scattering properties, accuracy, and efficiency of the method. Changes in spattering spatial distribution resulting from variations in processing parameters, including laser power, scan speed, and chamber pressure, were investigated. Some of these conditions resulted in the formation of a deep keyhole zone. The results demonstrated that monitoring radar cross-section (RCS) of the spatters could serve as a metric to distinguish between conditions that lead to a deeper keyhole and those that either do not create a keyhole zone or result in a shallower keyhole. Additionally, the concept of the “sphere-of-influence (SoI)” is used as a tool for improving computational efficiency and potential use in method validation. The insights from this study have the potential to contribute to the advancement of real-time LPBF monitoring, presenting possibilities for improved quality control and defect detection in AM processes.

Mesh division plays an important role in applications of the finite element method (FEM). The proposed research shows that under the same order, the equilateral triangular meshes have the most uniform dispersion distribution. The isosceles triangles with equal base and height have more uniform dispersion error than the square meshes, while the maximum phase error is similar. Taking the rectangular waveguide as an example, the relative errors in the cut-off frequency are analyzed based on different meshes. The numerical results show that under the same interpolation order and node numbers, the relative error of isosceles triangles with equal base and height for TE10 mode is the smallest. The results are useful in choosing appropriate element order, node density and mesh shape when applying FEM.

Digital dermatitis (DD) is an emerging disease in feedlot cattle. Our objective was to identify animal- and feedlot-level risk factors for DD by analyzing individual animal health records (n = 1,209,883) and feedlot-level records from western Canadian feedlots (n = 28) between 2014 and 2018, inclusive. The risk of a DD diagnosis was higher (incidence rate ratio (IRR) = 2.08, 95% CI 1.52 to 2.86) in cattle sourced from confined background operations (CB) versus cattle sourced from auction markets (AM). Conversely, ranch direct (RD) cattle were (IRR = 0.02, 95% CI 0.04 to 0.30) lower risk than AM cattle of being diagnosed with DD. The risk of being diagnosed with DD was higher in females than in males. The magnitude of the risk in females over males was influenced by annual DD incidence in low morbidity years (2014, 2017, and 2018) (IRR = 2.02, 95% CI 1.27 to 3.19), medium morbidity years (2016) (IRR = 2.95, 95% CI 1.64 to 5.33), and high morbidity years (2015) (IRR = 5.41, 95% CI 3.27 to 8.95). At the feedlot-level, the risk of a diagnosis of DD was lower in small capacity (SCF) versus large capacity feedlots (LCF) (IRR = 0.24, 95% CI 0.05 to 0.76). Future research should focus on identifying factors that may propagate disease transmission between cattle of different sexes and from different acquisition sources.

As a “medicine food homology” plant, the Piper betle L. has the characteristics of spicy, slightly sweet, and warm in nature, which can be used for treating cold, cough, stomachache, and eczema. The leaves have a strong and spicy aromatic smell and are widely used in chewables in Asia. Chemical analysis showed that the Piper betle L. contains nutrients and other chemical ingredients, including protein, starch, fat, essential oils, phenols, alcohols, ketones and alkaloids, etc. Modern pharmacological studies suggest that Piper betle L. is qualified with antimicrobial, antioxidant, anticancer, insect-resistant, anti-inflammatory, anti-malaria, and anti-glycosylation effect and so on. This article systematically reviews the material foundation and biological activity of Piper betle L., providing a reference for the further research and rational development.

The Arabidopsis thaliana ASYMMETRIC LEAVES2 (AS2) gene is responsible for the development of flat, symmetric, and extended leaf laminae and their veins. The AS2 gene belongs to the plant-specific AS2-LIKE/LATERAL ORGAN BOUNDARIES (LOB)-domain (ASL/LBD), which consists of 42 proteins in Arabidopsis with a conserved amino-terminal domain known as the AS2/LOB domain, and a variable carboxyl-terminal region. AS2/LOB domain consists of an amino-terminal (N-terminal) that contains a cysteine repeat (the C-motif), a conserved glycine residue, and a leucine-zipper-like. AS2/LOB domain has been characterised in plants such as A. thaliana, Zea mays, and Oryza sativum. Nevertheless, it remains uncharacterised in cassava (Manihot esculenta). Characterisation and identification of cassava ASL/LBD genes using the computational algorithms, hidden Markov model profiles (PF03195), determined 55 ASL/LBD genes (MeASLBD1 to MeASLBD55). The gene structure and motif composition were conserved in MeASLBDs, while the expression profiles of these genes were highly diverse, implying that they are associated with diverse functions. Weighted gene co-expression network analysis (WGCNA) of target genes and promoter analysis suggest that these MeASLBDs may be involved in hormone and stress responses. Furthermore, the analysis of cis-regulatory elements in promoter regions suggested that MeASLBDs may be involved in the plant phytohormone signal response. The transcriptome data of cassava under biotic and abiotic stresses revealed that MeASLBD46 and MeASLBD47 greatly respond to disease and drought. The MeASLBD47 gene was selected for functional analysis. The result indicated that MeASLBD47 significantly mitigated the virulence of cassava bacterial blight (XamCHN11) through Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) and Virus-induced gene silencing (VIGS). These findings provided a comprehensive analysis of ASL/LBD genes and laid the groundwork for future research to understand ASL/LBD genes.

Seeking new strategies to tune the intrinsic defect and optimize the thermoelectric performance via no or less use of external doped elements (i.e., plain optimization) is an important method to realize the sustainable development of thermoelectric materials. Meanwhile, creating dislocation defects in oxide systems is quite challenging because the rigid and stiff ionic/covalent bonds can hardly tolerate the large strain energy associated with dislocations. Herein, taking BiCuSeO oxide as an example, the present work reports a successful construction of dense lattice dislocations in BiCuSeO by self-doping of Se at the O site (i.e., SeO self-substitution), and achieves plain optimization of the thermoelectric properties with only external Pb doping. Owing to the self-substitution-induced large lattice distortion and the potential reinforcement effect by Pb doping, high-density (about 3.0 × 1014 m−2) dislocations form in the grains, which enhances the scattering strength of mid-frequency phonon and results in a substantial low lattice thermal conductivity of 0.38 W m−1 K−1 at 823 K in Pb-doped BiCuSeO. Meanwhile, PbBi doping and Cu vacancy markedly improve the electrical conductivity while maintaining a competitively high Seebeck coefficient, thereby contributing to a highest power factor of 942 μW m−1 K−2. Finally, a remarkably enhanced zT value of 1.32 is obtained at 823 K in Bi0.94Pb0.06Cu0.97Se1.05O0.95 with almost compositional plainification. The high-density dislocation structure reported in this work will also provide a good inspiration for the design and construction of dislocations in other oxide systems.

Abstract A well‐conditioned volume‐surface integral equation, called the volume integral equation‐combined field integral equation, is applied to analyse electromagnetic (EM) scattering from arbitrarily shaped three‐dimensional composite objects comprising both inhomogeneous bi‐anisotropic material and closed perfect electric conductors (PECs). The equivalent surface and volume currents are respectively expanded using the commonly used RWG and SWG basis functions, while a matrix equation is derived by the method of moments. Because the magnetic field integral equation is involved in modelling the surface electric current, and the constitutive parameters are all tensors, some new kinds of singularities are encountered and properly handled in the filling process of the impedance matrix. Several numerical results of EM scattering from composite bi‐anisotropy and closed PEC objects are shown to illustrate the accuracy and efficiency of the proposed scheme. The validity of the continuity condition of electric flux enforced on the bi‐anisotropy‐PEC interfaces, which can be used to eliminate the volumetric electric unknowns, is also verified.

The interpolation errors of the higher order bivariate Lagrange polynomial interpolation based on the rectangular, right and equilateral triangular interpolations are measured by using the maximum and root-mean-square (RMS) errors. The error distributions of above three kinds of interpolations are analyzed to find the regions having the smallest interpolation error. Both analytical and numerical results show that the right triangular interpolation is the most efficient interpolation method. Although both the maximum and RMS errors of the right triangular interpolation are larger than that of the rectangular interpolation, the number of data points used in the triangular interpolation is up to 50% less than that used in the rectangular one. On the other hand, the equilateral triangular interpolation using the regions inside a big triangle as interpolation area is proved to be the most accurate interpolation method. The interpolation errors of the equilateral triangular are almost half of that of the rectangular interpolation. In addition, the right triangular, equilateral triangular and rectangular interpolations for the third and fourth orders are applied to accelerate the calculation of doubly periodic Green’s function (PGF).

Model assisted probability of detection (MAPoD) is crucial for quantifying the inspection capability of a nondestructive testing (NDT) system which uses the coil or probe to sense the size and location of the cracks. Unfortunately, it may be computationally intensive for the simulation models. To improve the efficiency of the MAPoD, in this article, an efficient 3D eddy current nondestructive evaluation (ECNDE) forward solver is proposed to make estimations for PoD study. It is the first time that singular value decomposition (SVD) is used as the recompression technique to improve the overall performance of the adaptive cross approximation (ACA) algorithm-based boundary element method (BEM) ECNDE forward solver for implementation of PoD. Both the robustness and efficiency of the proposed solver are demonstrated and testified by comparing the predicted impedance variations of the coil with analytical, semi-analytical and experimental benchmarks. Calculation of PoD curves assisted by the proposed simulation model is performed on a finite thickness plate with a rectangular surface flaw. The features, which are the maximum impedance variations of the coil for various flaw lengths, are obtained entirely by the proposed model with selection of the liftoff distance as the uncertain parameter in a Gaussian distribution. The results show that the proposed ACA-SVD based BEM fast ECNDE forward solver is an excellent simulation model to make estimations for MAPoD study.

A new generalized volume-surface integral equation, volume integral equation-combined field integral equation (VIE-CFIE), is proposed to analyze the electromagnetic (EM) scattering from composite objects comprised of both perfect electric conductor (PEC) and inhomogeneous bi-isotropic material. By discretizing the objects using triangular and tetrahedral cells on which the commonly used Rao-Wilton-Glisson (RWG) and Schaubert-Wilton-Glisson (SWG) basis functions are respectively defined, the matrix equation is derived using the method of moments (MoM) and the Galerkin's testing. Furthermore, the continuity condition (CC) of electric flux is explicitly enforced on the PEC and bi-isotropy interfaces. In this way, the number of volumetric unknowns is reduced based on the same set of meshes, particularly for the thin coated PEC objects. A convenient way to embed the CC into the context of MoM solution is provided in detail. Several numerical results of EM scattering from coated PEC objects are shown to illustrate the accuracy and efficiency of the proposed method.

An absorptive/transmissive frequency selective surface (ATFSS) with absorption bands at both sides of a passband is presented. Equivalent circuits of the ATFSS that consists of a lossy frequency selective surface (FSS) and a lossless FSS were modeled. To improve the rejection at an undesired band, a transmission zero was introduced and controlled by loading the lossless FSS with four-legged loaded slots. The parasitic passband was suppressed when the cross structure in the lossless FSS was loaded with resistance. In order to expand the absorption band, loaded dipoles were utilized for the lossy FSS design. An ATFSS with wide absorption bands was realized after three ATFSSs with different performances were investigated. The proposed ATFSS was fabricated and measured. The measurement results showed that a passband at around 5 GHz with a minimum insertion loss of 0.92 dB was obtained. Within an ultrawide band from 2.8 to 11.4 GHz with |S11|

This paper presents an active frequency selective surface (AFSS) with a wide reconfigurable passband. The tuning mechanism was investigated with an equivalent circuit which consists of a parallel L-C resonant circuit and a series L-C resonant circuit. A cross-loop slot was selected as a unit cell, and varactor diodes were added across the slot to tune the passband. The effects of various bias configurations on the transmission coefficients were studied. The simulation results showed that a reconfigurable passband ranged from 2.92 to 5.74 GHz was obtained with a variable capacitance from 0.8 to 0.1 pF. A prototype of the proposed AFSS was fabricated and measured. The measurement results showed that the passband was altered from 2.94 to 5.66 GHz if the biasing voltage of varactor diodes was increased from 4 to 18V. The measurement and simulation results agree well with each other.

A volume integral equation (VIE) based on the mixed-potential representation is presented to analyze the electromagnetic scattering from objects involving inhomogeneous bi-anisotropic materials. By discretizing the objects using tetrahedrons on which the commonly used Schaubert-Wilton-Glisson (SWG) basis functions are defined, the matrix equation is derived using the method of moments (MoM) combined with the Galerkin's testing. Further, adopting an integral strategy of tetrahedron-to-tetrahedron scheme, the multilevel fast multipole algorithm (MLFMA) is proposed to accelerate the iterative solution, which is further improved by using the spherical harmonics expansion with a faster implementation and low memory requirement. The memory requirement of the radiation patterns of basis functions in the proposed MLFMA is several times less than that in the conventional MLFMA.

In this study, the complete chloroplast genome of Loropetalum chinense var. rubrum Yieh was sequenced and characterized. The chloroplast genome is 159,427 bp in length, and contains a large single-copy (LSC) region of 88,185 bp and a small single-copy (SSC) region of 18,772 bp separated by a pair of inverted repeat (IR) regions of 26,235 bp. There are 128 genes in the genome including 83 protein-coding, 37 tRNA, and eight rRNA genes. The overall GC is 38.0% and the LSC, SSC, and IR regions are 36.1, 32.7, and 43.1%, respectively. Phylogenetic analysis of L. chinense var. rubrum fully resolved it in a clade with L. subcordatum. This complete chloroplast genome will provide valuable insight into evolution, molecular breeding, and phylogenetic analysis of Loropetalum species.

In this article, a novel hybrid method of multilevel kernel degeneration and adaptive cross approximation (MLKD-ACA) algorithm with integral kernel truncations is proposed to accelerate solving integral equations using method of moments (MoM), and to simulate the 3D eddy current nondestructive evaluation (NDE) problems efficiently. The MLKD-ACA algorithm with an integral kernel-truncations-based fast solver is symmetrical in the sense that: (1) the impedance matrix, which is generated by the MoM representing the interactions among the field and source basis functions, is symmetrical; (2) the factorized form of the integral kernel (Green’s function) resulted from degenerating it by the Lagrange polynomial interpolation is symmetrical; (3) the structure of the truncated integral kernel for the interactions among the blocks, which ignores the trivial ones of the far block pairs, is symmetrical using the integral kernel truncations technique. The impedance variations predicted by the proposed symmetrical eddy current NDE solver are compared with other methods in benchmarks to show the remarkable accuracy and efficiency.

Here, we report the complete chloroplast genome of Pittosporum brevicalyx. The genome is 153,388 bp in size, which is comprised of a large single-copy (LSC) region of 84,724 bp, a small single-copy (SSC) region of 18,716 bp, and two inverted repeat (IR) regions of 24,974 bp. The overall GC content of the plastome was 38.3%. The new sequence comprised 127 unique genes, including 82 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. Phylogenetic analysis showed that P.brevicalyx was close to Pittosporum kerrii and Pittosporum eugenioides. These data may providing useful information for phyletic evolution of P.brevicalyx within the Pittosporaceae family.

Air bearing has been widely applied in ultra-precision machine tools, aerospace and other fields. The restrictor of the porous material is the key component in air bearings, but its performance is limited by the machining accuracy. A combination of optimization design and material modification of the porous alumina ceramic membrane is proposed to improve performance within an air bearing. Porous alumina ceramics were prepared by adding a pore-forming agent and performing solid-phase sintering at 1600 °C for 3 h, using 95-Al2O3 as raw material and polystyrene microspheres with different particle sizes as the pore-forming agent. With 20 wt.% of PS50, the optimum porous alumina ceramic membranes achieved a density of 3.2 g/cm3, a porosity of 11.8% and a bending strength of 150.4 MPa. Then, the sintered samples were processed into restrictors with a diameter of 40 mm and a thickness of 5 mm. After the restrictors were bonded to aluminum shells for the air bearing, both experimental and simulation work was carried out to verify the designed air bearing. Simulation results showed that the load capacity increased from 94 N to 523 N when the porosity increased from 5% to 25% at a fixed gas supply pressure of 0.5 MPa and a fixed gas film thickness of 25 μm. When the gas film thickness and porosity were fixed at 100 μm and 11.8%, respectively, the load capacity increased from 8.6 N to 40.8 N with the gas supply pressure having been increased from 0.1 MPa to 0.5 MPa. Both experimental and simulation results successfully demonstrated the stability and effectiveness of the proposed method. The porosity is an important factor for improving the performance of an air bearing, and it can be optimized to enhance the bearing’s stability and load capacity.

The accurate quantification of antimicrobial use (AMU) in production animals is critical for monitoring trends in exposure to antimicrobial drugs (AMD) over time and examining potential associations with antimicrobial resistance in bacteria. In this study, a census sample of cattle was used to quantify individually-dosed and in-feed AMU as both numbers of animal daily doses (nADD) and total grams of AMD (gAMD) used in cattle placed in 36 western Canadian feedlots between 1-November, 2008 and 31-October, 2012; representing about 21.5% of fed cattle in Canada during that time period. Of the ~2.6 million cattle placed during the 48-month period, 45% were calves, 63% were male, 62% arrived in the fall or winter, and 39% were assessed as high risk for developing bovine respiratory disease (BRD). The proportion of cattle categorized as high risk (HR) for developing BRD was consistent over the 4 years of placement cohorts. Both medically important AMU and ionophore use were summarized but presented separately. A decrease in AMU was observed over the study period, both as nADD and total gAMD, which was primarily driven by a decline in the in-feed administration of tetracyclines. Most in-feed AMU was directed toward prevention and control of liver abscesses. The majority of individually dosed AMU was administered as metaphylaxis to address BRD risks, with category III AMD (medium importance to human medicine as categorized by Health Canada Veterinary Drugs Directorate) used most frequently. Not surprisingly, risk level for developing BRD influenced parenteral AMD exposures, with 95% of cattle categorized as being HR for developing BRD receiving individually dosed AMD compared to 59% of cattle categorized as being low risk (LR) for developing BRD. Cattle categorized as HR for developing BRD were more likely to receive macrolides for BRD metaphylaxis compared to cattle categorized as LR for developing BRD, and cattle categorized as LR for developing BRD were more likely to receive tetracycline for the same purpose. In summary, these data provide an unprecedented representation of AMU in fed cattle in western Canada and direction for future monitoring of AMU in fed cattle.

Aiming at the low-frequency line spectrum noise characteristics of power equipment noise, based on the principle of energy degradation, this paper combines the energy degradation sound insulation structure with the dynamic vibration absorption technology for the first time and applies it to the research field of noise control of power equipment in substations. Dynamic vibration absorption technology is used to effectively control low-frequency vibration and noise. Considering that there is an upper limit to the capacity of DVA, the sound-vibration energy degradation design of the transformer is completed by setting a sound insulation structure on the outside of the original transformer housing. It is analyzed that the vibration energy of the sound insulation structure in the specific frequency band is significantly reduced compared to the transformer housing, realizing efficient degradation of the vibration energy of the transformer housing and effective isolation of sound radiation. Through the optimized design of dynamic vibration absorption for the sound insulation structure, the structural sound isolation ability at the target frequency is further strengthened, and the system noise radiation level is greatly reduced under the action of multiple mechanisms at the target frequency, verifying the feasibility and high efficiency of the optimal DVAs energy degradation design of the transformer. [ABSTRACT FROM AUTHOR]

In this article, a metamodeling approach based on non-intrusive polynomial chaos expansion (PCE) with least angle regression (LAR) method is used in boundary element analysis for a model-assisted probability of detection (MAPoD) study of eddy current nondestructive testing (NDT) systems. The LAR-PCE metamodel represents the NDT system model responses by a set of coefficients with the polynomial basis functions in lieu of pure kernel degeneration accelerated boundary element method (KD-BEM) based physical model. Both the computational accuracy and efficiency of the LAR-PCE metamodel over the ordinary least squares (OLS) based PCE metamodel are demonstrated by testing the 3D eddy current NDT benchmarks with different system setups, flaw lengths and widths. The simulation results show two digits accuracy of the PoD metrics compared with the ones achieved by the KD-BEM based physical model as the benchmark. The LAR-PCE metamodel has remarkable improvements in computational efficiency over the OLS-PCE metamodel and accelerates the MAPoD study. [ABSTRACT FROM AUTHOR]

The radiation characteristics of circular arc antennas are studied by applying the method of moments (MoM) to solve the electric field integral equation (EFIE). Based on the triangular current distribution of small circular arc antennas, the analytical expression of radiation fields of circular arc antennas is derived. It is found that the circular arc antenna is equivalent to a superposition of an electric dipole and a magnetic dipole, resulting in near isotropic radiation pattern. Finally, both MoM and CST simulations show that the small arc antenna can realize the near isotropic radiation pattern. [ABSTRACT FROM AUTHOR]