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The 3-D ultrasound (US) imaging addresses the limitation in field-of-view (FOV) in conventional 2-D US imaging by providing 3-D viewing of the anatomy. The 3-D US imaging has been extensively adapted for diagnosis and image-guided surgical intervention. However, conventional approaches to implement 3-D US imaging require either expensive and sophisticated 2-D array transducers or external actuation mechanisms to move a 1-D array mechanically. Here, we propose a 3-D US imaging mechanism using an actuated acoustic reflector instead of the sensor elements for volume acquisition with significantly extended 3-D FOV, which can be implemented with simple hardware and compact size. To improve image quality on the elevation plane, we implemented the synthetic aperture focusing (SAF) method according to the diagonal geometry of the virtual element array in the proposed imaging mechanism for elevation beamforming. We first evaluated the proposed imaging mechanism and SAF with simulated point targets and cyst targets. The results of point targets suggested improved image quality on the elevation plane, and the results of cysts targets demonstrated a potential to improve 3-D visualization of human anatomy. We built a prototype imaging system with a 3-D FOV of 38 mm (lateral) by 38 mm (elevation) by 50 mm (axial) and collected data in imaging experiments with phantoms. Experimental data showed consistency with simulation results. The SAF method enhanced quantifying the cyst volume size in the breast mimicking phantom compared with no elevation beamforming. These results suggested that the proposed 3-D US imaging mechanism could potentially be applied in clinical scenarios. [ABSTRACT FROM AUTHOR]

The pore ratio is an important parameter affecting the stability and safety of tailings reservoirs; however, the relationship between the pore ratio and physical properties of tailings sand has not been researched in-depth. In this paper, using the tailings from a tungsten mine in southern Shaanxi as a case study, the correlation between the minimum void ratio and related parameters is analyzed, based on laboratory test data, and the optimal marginal distribution function of the parameters is determined. The Gumbel-Hougard copula function that best describes the correlation between parameters is identified, and it is used to establish the joint probability distribution model of the three parameters, and the guarantee rate α is introduced to estimate and analyze the minimum void ratio. The results show that the optimal edge distribution of the fine particle content and specific gravity follows a truncated normal distribution, and the optimal edge distribution of the minimum void ratio follows a logarithmic normal distribution. According to AIC criterion, the Gumbel-Hougard copula is the best three-dimensional copula function to fit the minimum void ratio and related parameters. When the guarantee rate α is 0.485, the joint probability distribution model achieves optimal performance in terms of estimating the minimum void ratio. The maximum error of the estimation is 1.99%, which is verified through data, and the estimation meets the requirements for practical engineering. The method proposed in this paper uses the existing measured data to establish a joint probability distribution model and combines the collected fine particle content and specific gravity data with the guarantee rate to estimate the minimum void ratio, providing a novel basis for the study of the physical properties of tailings. [ABSTRACT FROM AUTHOR]

• Shell offset of lattice helps to improve geometric efficiency on mechanical property. • Simulation models with CT manufacturing deviations were used to reveal the deformation mechanisms. • Increasing second moment of lattice without plastic hinges contributes to the enhancement mechanisms. Lattice structure based on triply periodic minimal surface (TPMS) has received increasing interests due to exceptional lightweight and excellent performance. Recent studies are focusing on improving geometric efficiency of TPMS lattice structures. This paper presents an optimization approach of shell offset to improve mechanical and energy absorption of TPMS lattices. Additive manufactured lattices with four TPMS units were detected by Micro-CT to evaluate the micro-pores and manufacturing deviation of Ti6Al4V parts. Mean deviation was novelty loaded into simulation models to reveal the enhancement mechanisms of lattice structures, confirmed by experimental tests. The simulation results reproduce the experimental process including the elastic region, stress drop and plateau, indicating its good predictability. Shell offset design leads to a significant improvement on mechanical properties and energy absorption by maximum values of 244.9% and 312.7% respectively. This is due to the increase of second moment of area by shell offset, contributing to successive and stable layer-by-layer deformation mechanism of Diamond, Gyroid and I-WP lattices in which bending moment and torque are dominant. But excessive shell offset should be avoided for sheet Primitive due to the weakening effect of plastic hinge. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A machine learning and Python assisted method was proposed to predict six kinds magnetic properties of Fe-based amorphous and nanocrystalline alloys. • Artificial Neural Network algorithm showed the best predictive ability with determination coefficient of>0.90. • An alloy Fe 83 B 9 P 3 C 4 Nb 1 with desired magnetic properties was designed and verified experimentally. • The predicted magnetic properties by Artificial Neural Network are in very good agreement with experimental measured ones. We report a machine learning (ML) and Python assisted strategy to accelerate the design and verification of Fe–based amorphous and nanocrystalline alloy with desired properties. Linear Regression (LR), Support Vector Regression (SVR), Decision Tree Regression (DTR), Artificial Neural Network (ANN) and Random Forest Regression (RFR) are employed to build prediction models of soft magnetic properties, such as saturation magnetic flux density (B s), coercivity force (H c), magnetization (M s), Curie temperature (T c), maximum permeability (µ max) and effective permeability (µ e). It is found that ANN has the excellent fitting ability with largest coefficient of determination (R2) to predict the soft magnetic properties of new designed alloys. Then, Python screening is used to find the alloy compositions with best soft magnetic properties of Fe–B–P–C–Nb system. Finally, Fe 83 B 9 P 3 C 4 Nb 1 alloy with good soft magnetic properties has been designed and prepared to verify. It is indicated that the soft magnetic properties of Fe 83 B 9 P 3 C 4 Nb 1 amorphous and nanocrystalline alloy predicted by ML are in agreement with the experimental measured results. These findings indicate that ML and Python assisted approach can accelerate the design of Fe–based alloys with desired properties accurately. [ABSTRACT FROM AUTHOR]

Abstract: Methods for “cleaning up” (or recognizing) states of a neural network are crucial for the functioning of many neural cognitive models. This process takes a noisy approximation of a state and recovers the original information. As a particular example, we consider the cleanup required for the use of Vector Symbolic Architectures, which provide a method for manipulating symbols using a fixed-length vector representation. To recognize the result of these manipulations, a mechanism for cleaning up the resulting noisy representation is needed, as this noise increases with the number of symbols being combined. While these symbolic manipulations have previously been modelled with biologically plausible neurons, this paper presents the first spiking neuron model of the cleanup process. We demonstrate that it approaches ideal performance and that the neural requirements scale linearly with the number of distinct symbols in the system. While this result is relevant for any biological model requiring cleanup, it is crucial for VSAs, as it completes the set of mechanisms needed to provide a full neural implementation of symbolic reasoning. [Copyright &y& Elsevier]

Functionally graded materials (FGMs) such as polymer/ceramic composite have emerged as a prospective candidate for orthopedic implants, as they enable the incorporation of diverse material properties with mechanical biomimetic and biocompatibility of bone scaffolds. This study presents a novel approach for fabricating FGM scaffolds using a simplified additive manufacturing and impregnation-curing process, aiming to develop hydrophilic scaffolds with excellent mechanical properties. The graded composition of the scaffold was confirmed through micro-CT and SEM, with hydroxyapatite (HA) particles embedded on the surface of Polyactive acid (PLA) scaffold. The outermost layer exhibited a uniform distribution of HA with rough morphology, enhancing the hydrophilicity by 20 %. While the internal graded pure PLA core contributed to excellent mechanical strength. By adopting a programmable triply periodic minimal surfaces (TPMS) approach, the relative density of the PLA core has been adjusted to tailor scaffold's mechanical properties. This innovative fabrication method opens avenues for polymer/ceramic composite development in orthopedic implants to enhance long-term stability and biocompatibility. [Display omitted] • Polymer/ceramic functionally graded material scaffold has been fabricated by a novel additive manufacturing. • The ceramics' hydrophilicity and polymer's toughness are integrated into the composite scaffold. • Continuous gradient changes between different materials enhance the bonding properties and avoid delamination cracks. [ABSTRACT FROM AUTHOR]

The hippocampus is critical for learning and memory and may be separated into anatomically-defined hippocampal subfields (aHPSFs). Hippocampal functional networks, particularly during resting state, are generally analyzed using aHPSFs as seed regions, with the underlying assumption that the function within a subfield is homogeneous, yet heterogeneous between subfields. However, several prior studies have observed similar resting-state functional connectivity (FC) profiles between aHPSFs. Alternatively, data-driven approaches investigate hippocampal functional organization without a priori assumptions. However, insufficient spatial resolution may result in a number of caveats concerning the reliability of the results. Hence, we developed a functional Magnetic Resonance Imaging (fMRI) sequence on a 7 T MR scanner achieving 0.94 mm isotropic resolution with a TR of 2 s and brain-wide coverage to (1) investigate the functional organization within hippocampus at rest, and (2) compare the brain-wide FC associated with fine-grained aHPSFs and functionally-defined hippocampal subfields (fHPSFs). This study showed that fHPSFs were arranged along the longitudinal axis that were not comparable to the lamellar structures of aHPSFs. For brain-wide FC, the fHPSFs rather than aHPSFs revealed that a number of fHPSFs connected specifically with some of the functional networks. Different functional networks also showed preferential connections with different portions of hippocampal subfields. [ABSTRACT FROM AUTHOR]

High-purity silicon power was doped with standard solutions containing 15 elements, and a high-purity indium tablet was prepared by the melting of indium pellets. An In-Si tablet, which is mechanically stable and thus suitable as a calibration sample, was prepared by our pressing the doped silicon power on the high-purity indium tablet. The matrix effect was studied by our investigating the variations of measured mass fractions (standard relative sensitivity factor, StdRSF, calibration) of doped impurities in the In-Si tablet, which provides a series of matrixes with different mass ratios of In to Si. For all the elements, the relative standard deviations of the measured mass fractions of impurities were less than 30%. The RSFs of the glow discharge mass spectrometer (Element GD) were obtained, and the results showed that three RSFs derived from the In-Si tablet with low, intermediate and high mass ratios of In to Si, respectively, agreed with the mean RSF within an uncertainty interval of 30%. The measurement of Fe and Al matrix certified reference materials further demonstrated that the RSFs generated from a matrix can be used for the calibration of another matrix, and the uncertainty was within 30%. Finally, another doped silicon powder was measured with the glow discharge mass spectrometer, which was calibrated by the mean RSFs from the In-Si tablet, and the analytical results obtained by glow discharge mass spectrometry are in good agreement with the analytical results obtained by high-resolution inductively coupled plasma mass spectrometry.ᅟ [ABSTRACT FROM AUTHOR]

Glow discharge mass spectrometry (GDMS) with its high resolution, low limit of determination and wide linear dynamic range is a powerful technique for direct analysis of high purity solid metals. Similar to the drawback of other direct solid sampling methods, a drawback of this technique is the lack of appropriate pure certified reference materials to calibrate the instrument, so that it is often used for semi-quantity analysis. A new calibration procedure using synthetic calibration samples by the doping-melting method was developed to obtain more accurate and traceable analytical results. The calibration samples were prepared from high purity copper powder doped with standard solutions of graduated and defined concentration. And then a part of them was melted into bulks and another was pressed to tablets. The homogeneity of both types of samples was measured by GDMS and for the doped tablets, relative deviations of the IBRs of both sides for 45 elements were mostly less than 10%. For the doped bulks, some problems such as the segregation effect and analyte losses happened for most elements; so satisfactory homogeneity was obtained for only 9 elements, for which nearly all relative deviations of the IBRs of both sides were less than 5%. Relative sensitivity factors of 9 and 45 elements in the copper matrix were obtained by calibration of GDMS with doped bulks and doped tablets, respectively. The RSF values obtained by calibration with doped tablets were compared with values derived from standard RSFs and the large differences demonstrated that matrix-adapted calibration was necessary when the impurities were measured accurately by using the instrument, especially for the rare earth elements. Then the 9 RSFs determined using tablets and bulks were compared and the results showed that relative deviations of them in most cases were less than 10%. The correlation coefficients of the calibration curves obtained by using the doping-melting method were better than those obtained using the doping-pressed method and the uncertainties of RSFs were smaller. Several copper CRMs were measured to validate the calibration procedures. The results revealed that the measured values using the two types of calibration samples were in agreement with the certified values. The results revealed that the calibration results of Fe and Ni coming from calibration samples prepared by using the two types of methods were in agreement with the certified values. [ABSTRACT FROM AUTHOR]

• Dual-graded lattices were created via fusion algorithm of Sigmoid-Boltzmann. • Graded artificial vertebrae demonstrates reduced stress shielding on endplates. • Dual-graded TPMS lattice shows mechanical bionics and longer fatigue life. Additive manufacturing (AM) is revolutionizing the design and fabrication of orthopedic implants, enabling the creation of complex graded structures to enhance biomechanical bionics. This study aims to enhance fatigue life and reduce stress shielding for a long-term stability by using functionally graded lattice. Various lattice with minimal surface, including uniform array, Z- axis graded, and dual-graded Gyroid, were designed and fabricated by selective laser melting (SLM), followed by mechanical and fatigue tests for validation of design objectives. With a novel Sigmoid-Boltzmann fusion algorithm, the dual-graded lattice enhances the artificial vertebral body (AVB) with an 11 % increase in strength, >200 % improvement in fatigue life and reduced stress shielding on the contact surface, benefiting long-term implant stability and biomechanical fidelity. It displayed outstanding resistance to fatigue crack propagation due to superior load-bearing capacity and energy absorption capabilities contributed by the graded central region. The findings highlight the significance of biomimetic design principles and offer insights into the optimization of orthopedic implants using dual-graded lattice. [Display omitted] [ABSTRACT FROM AUTHOR]

Copper matrix-matched calibration samples were prepared by doping high purity copper powders (99.999%, 500–600 μm) with multi-element standard solutions with a total of 72 elements, and then the relative sensitivity factors (RSFs) of the 72 elements in both microsecond-pulsed and continuous direct current (dc) modes were determined by using Element GD type glow discharge mass spectrometry (GD-MS). The ability of pulsed and continuous dc-GD-MS to quantitatively determine trace elements in copper was demonstrated after calibration using the RSFs. The results showed that the uncertainty level of GD-MS analysis after calibration was comparable with that of ICP-MS and ICP-OES analysis. In order to standardize calibration sample preparation procedures, the doping concentration, pressed powder tablet compactness and tablet homogeneity were optimized. Good recovery (85% to 115%) was obtained. Good pressed powder tablet compactness and tablet homogeneity were obtained, which were expressed as relative standard deviations (<5%) of 6 times GD-MS analysis. Satisfactory repeatability of about 15% (RSD) for continuous and 10% (RSD) for pulsed dc-GD-MS was obtained by strictly controlling the intensity of the matrix to keep it stable when replacing graphite parts. Good reproducibility (RSD < 10%) was obtained after timely detector calibration, so the determined RSFs could remain constant and valid in an instrument for a long time. Under the optimized conditions mentioned above, the RSFs of the total 72 elements in both continuous and pulsed modes were determined and compared. The comparison of RSFs showed that the general trends of the two sets of RSFs were very similar; however, the RSFs in pulsed mode were 2–40% lower than those in continuous mode in most cases. Therefore, a dedicated RSF table for each mode is recommended to achieve accurate and quantitative analysis. The comparison of RSFs in this work with standard RSFs provided by the manufacturer of Element GD revealed that the accepted uncertainty of a factor of two was met for almost all investigated elements in both modes. The accuracy of the RSFs was validated by analyzing three Cu-matrix CRMs. The relative expanded uncertainties (Urel, k = 2) of measured results by using pulsed dc-GD-MS, including the uncertainty of measurement repeatability and RSF, were less than 20%, which was much lower than those obtained by continuous dc-GD-MS (Urel < 30%). [ABSTRACT FROM AUTHOR]

[Display omitted] • Bioinspired IPCs of Ti6Al4V and PEEK show robust interfacial connections and improved mechanical performance. • Synergistic interaction between the phases enhances toughness, energy absorption, and maintains a low elastic modulus. • Efficient stress transfer mechanisms contribute to stress dispersion and resistance to crack propagation, resulting in enhanced material performance. Bioinspired interpenetrating phase composites (IPCs) present a promising strategy for augmenting the mechanical properties of materials, thereby synergistically enhancing the strength and fracture toughness of orthopedic implants. In this study, Ti6Al4V-PEEK IPCs were fabricated by pressing molten PEEK into additively manufactured Ti6Al4V scaffolds designed using minimal surface structures. The mutual spatial interpenetration and strong binding between Ti and PEEK were confirmed through CT detection and SEM analyses, revealing the presence of continuous constituents within biomimetic architectures. Due to interpenetration promoting interaction and efficient stress transfer of the two phases, IPCs enhances toughness and energy absorption by over 291% and 309% respectively while maintaining bone-compatible elastic modulus and higher strength. The mechanisms underlying stress dispersion, crack propagation resistance, and prolonged stress plateau period of IPCs were investigated through the utilization of digital image correlation (DIC) and finite element simulation techniques. Among the various types of IPCs investigated, Gyroid IPCs exhibit superior comprehensive mechanical properties, thereby facilitating the development of customized IPCs aimed at ensuring long-term stability in orthopedic implantation scenarios. [ABSTRACT FROM AUTHOR]

The ICML 2013 Workshop on Challenges in Representation Learning 1 1 http://deeplearning.net/icml2013-workshop-competition . focused on three challenges: the black box learning challenge, the facial expression recognition challenge, and the multimodal learning challenge. We describe the datasets created for these challenges and summarize the results of the competitions. We provide suggestions for organizers of future challenges and some comments on what kind of knowledge can be gained from machine learning competitions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel method of shell offset greatly improves the mechanical properties and energy absorption capacity. • Gyroid with shell offset is an excellent feature to control spatial volume fraction of TPMS sheet lattices with constant mechanical properties. • Manufacturing deviations of SLM detected by CT were taken into simulation models to determine the mechanism of performance improvement. Additive manufacturing has enabled surface-based sheet lattice to emerge as a new mechanical metamaterial with exceptional weight specific strength properties and multifunction. A novel design method of shell offset has been developed here for enhancement of mechanical properties and domain controllability of separated spaces by sheet lattice. Using selective laser melting, Ti6Al4V lattice samples were fabricated for compression experiments, followed by Micro-CT reconstruction. Manufacturing deviations with mean values of statistical analysis were taken into numerical simulations for prediction of mechanical properties. Investigation results show that increasing the shell offset is an effective strategy to improve mechanical properties and energy absorption of sheet lattices by more than 200% competing with net lattices, which is attributed to the higher second moment of area and successive layer-by-layer deformation mechanism of optimized unit type. In addition, a feasible adjustment region of 30–55% has been found, in which spatial volume fraction of the two independent void phases can be controlled for flow regulation of heat exchange without changing their mechanical properties. Those design concepts of sheet lattices will be valuable in future thermal management applications with lightweight protection. [ABSTRACT FROM AUTHOR]

Quantitative analysis method of impurities in high purity lanthanum oxide (La 2 O 3) by microsecond pulsed glow discharge mass spectrometry (Pulsed-GD-MS) was established. A similar-matrix-matched calibration strategy, i.e. , calibrating the GD-MS instrument with the relative sensitivity factors (RSFs) derived from a similar matrix (100% Cu) to the matrix (80% Cu + 20% La 2 O 3) to be analyzed was proposed. The feasibility of using the similar-matrix-matched calibration strategy was demonstrated by investigating the matrix effect in Pulsed-GD-MS. The accuracy of the method was validated by using La 2 O 3 RMs. Finally, 71 impurities in La 2 O 3 were quantitatively measured by Pulsed-GD-MS by using both mixing method and modified secondary cathode technique, and the results of main impurities were validated by HR-ICP-MS. In comparison to HR-ICP-MS, it had more advantages for Pulsed-GD-MS to determine some elements, which was difficult to dissolve such as Pt and Au, easy to be contaminated such as K, and difficult to be ionized in the ICP ion source like Cl. Compared with the mixing method, the modified secondary cathode technique showed some advantages, such as simpler sample pre-treatment, less sample amount, lower risks of contamination and lower limits of quantification. The purity of La 2 O 3 by subtracting 71 impurities from 100% was then measured by Pulsed-GD-MS. The results showed that the measurement uncertainty of purity using the similar-matrix-calibration strategy was almost one order magnitude lower than that using the calibration of commonly used StdRSFs due to the significantly reduced expanded uncertainty (cover factor k = 2) of impurities analysis to about 30%. Unlabelled Image • A calibration strategy for analysis of dielectrics by μs-Pulsed-GD-MS is proposed. • Matrix effect could be negligible in μs-Pulsed-GD-MS. • Total 71 impurities in La 2 O 3 could be quantified by using self-determined RSFs. • It has more advantages for Pulsed-GD-MS over HR-ICP-MS. • Modified secondary cathode method has lower limits of detection than mixing method. [ABSTRACT FROM AUTHOR]