High-harmonic upconversion driven by a mid-infrared femtosecond laser can generate coherent soft x-ray beams in a tabletop-scale setup. Here, we report on a compact ytterbium-pumped optical parametric chirped pulse amplifier (OPCPA) laser system seeded by an all-fiber front-end and employing periodically poled lithium niobate (PPLN) nonlinear media operated near the pulse fluence limits of current commercially available PPLN crystals. The OPCPA delivers 3 µm wavelength pulses with 775 µJ energy at 1 kHz repetition rate, with transform-limited 120 fs pulse duration, diffraction-limited beam quality, and ultrahigh 0.33% rms energy stability over >18 h. Using this laser, we generate soft x-ray high harmonics (HHG) in argon gas by focusing into a low-loss, high-pressure gas-filled anti-resonant hollow core fiber (ARHCF), generating coherent light at photon energies up to the argon L-edge (250 eV) and carbon K-edge (284 eV), with high beam quality and ∼1% rms energy stability. This work demonstrates soft x-ray HHG in a high-efficiency guided-wave phase matched geometry, overcoming the high losses inherent to mid-IR propagation in unstructured waveguides, or the short interaction lengths of gas cells or jets. The ARHCF can operate in the long term without damage and with the repetition rate, stability, and robustness required for demanding applications in spectromicroscopy and imaging. Finally, we discuss routes for further optimizing the soft x-ray HHG flux by driving He at higher laser intensities using either the signal (1.5 μm) or idler wavelengths (3 μm).
The 6G era necessitates advanced multiplexing techniques that fully utilize various physical dimensions, including time, frequency, polarization, and space to enhance the achievable bitrate per wavelength and satisfy growing demands for capacity and spectral efficiency. Power domain hybrid modulation (PDHM) emerges as a viable technology to overcome the orthogonal limitations inherent in existing multiplexing schemes. In this paper, we introduce an iterative successive interference cancelation (SIC) algorithm for coherent optical transmission systems employing PDHM. The proposed system multiplexes a 16-ary quadrature amplitude modulation (16-QAM) signal with a quadrature phase shift keying (QPSK) signal at distinct power ratios. With the proposed iterative SIC, the system performance is improved by about one order of magnitude.
To ensure effective management of medical devices, it is imperative that medical devices must be safe and inoffensive, and their management must be based on evidence. Thus, to help enhance the safety of medical devices, a new mechanism for the periodic compliance assessment of medical devices has been developed. The mechanism involves the assessment of general safety, electrical safety and performance parameters in line with international best practice. At the same time, the effective management of medical devices requires data and information related to medical devices and their lifecycle events, which can be obtained through the medical device management information system. The establishment and implementation of efficient management of medical devices, involves strengthening the capacities of medical devices’ management, in order to be able to respond to the current requirements of the health system, in such a way as to ensure the functionality of medical devices and the safe and efficient use of medical devices. Accordingly, the implementation of efficient management of medical devices is fundamental for providing qualitative, safe and efficient medical devices, which contributes to increasing the quality of medical services.
The use of digital twins (DTs) in the electric power industry and other industries is a hot topic of research, especially concerning the potential of DTs to improve processes and management. This paper aims to present approaches to the creation of DTs and models in general. It also examines the key parameters of these models and presents the challenges that need to be addressed in the future development of this field. Our analysis of the DTs and models discussed in this paper is carried out on the basis of identified key characteristics, which serve as criteria for an evaluation and comparison that sets the basis for further investigation. A discussion of the findings shows the potential of DTs and models in different sectors. The proposed recommendations are based on this analysis, and aim to support the further development and use of DTs. Research into DTs represents a promising sector with high potential. However, several key issues and challenges need to be addressed in order to fully realize their benefits in practice.
This article evaluates SiGe/Si heterojunction vertical tunnel field-effect transistor (VTFET-hetero) biosensors, using SiGe in the source region to enhance sensitivity. It detects smaller analyte concentrations for biomedical applications. Non-ideal sensor behavior is explained by steric hindrance and irregular probe/receptor positions. Based on the simulation results, sensitivity is determined for four different cases in which partially filled nanogaps have decreasing, increasing, concave, and convex profiles. Simulation shows concave step profiles having the highest sensitivity. The VTFET-hetero structure exhibits higher sensitivity than horizontal biosensors, achieving a sensitivity of 8.64 × 107 for immobilized charged biomolecules.
Cervical cancer, among the most frequent adverse cancers in women, could be avoided through routine checks. The Pap smear check is a widespread screening methodology for the timely identification of cervical cancer, but it is susceptible to human mistakes. Artificial Intelligence-reliant computer-aided diagnostic (CAD) methods have been extensively explored to identify cervical cancer in order to enhance the conventional testing procedure. In order to attain remarkable classification results, most current CAD systems require pre-segmentation steps for the extraction of cervical cells from a pap smear slide, which is a complicated task. Furthermore, some CAD models use only hand-crafted feature extraction methods which cannot guarantee the sufficiency of classification phases. In addition, if there are few data samples, such as in cervical cell datasets, the use of deep learning (DL) alone is not the perfect choice. In addition, most existing CAD systems obtain attributes from one domain, but the integration of features from multiple domains usually increases performance. Hence, this article presents a CAD model based on extracting features from multiple domains not only one domain. It does not require a pre-segmentation process thus it is less complex than existing methods. It employs three compact DL models to obtain high-level spatial deep features rather than utilizing an individual DL model with large number of parameters and layers as used in current CADs. Moreover, it retrieves several statistical and textural descriptors from multiple domains including spatial and time–frequency domains instead of employing features from a single domain to demonstrate a clearer representation of cervical cancer features, which is not the case in most existing CADs. It examines the influence of each set of handcrafted attributes on diagnostic accuracy independently and hybrid. It then examines the consequences of combining each DL feature set obtained from each CNN with the combined handcrafted features. Finally, it uses principal component analysis to merge the entire DL features with the combined handcrafted features to investigate the effect of merging numerous DL features with various handcrafted features on classification results. With only 35 principal components, the accuracy achieved by the quatric SVM of the proposed CAD reached 100%. The performance of the described CAD proves that combining several DL features with numerous handcrafted descriptors from multiple domains is able to boost diagnostic accuracy. Additionally, the comparative performance analysis, along with other present studies, shows the competing capacity of the proposed CAD.
Edward Bormashenko, Irina Legchenkova, Mark Frenkel
et al.
In this paper, informational (Shannon) measures of symmetry are introduced and analyzed for patterns built of 1D and 2D shapes. The informational measure of symmetry <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>H</mi><mrow><mi>s</mi><mi>y</mi><mi>m</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> characterizes the averaged uncertainty in the presence of symmetry elements from group <i>G</i> in a given pattern, whereas the Shannon-like measure of symmetry <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi mathvariant="sans-serif">Ω</mi><mrow><mi>s</mi><mi>y</mi><mi>m</mi></mrow></msub><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> quantifies the averaged uncertainty of the appearance of shapes possessing a total of <i>n</i> elements of symmetry belonging to group <i>G</i> in a given pattern. <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>H</mi><mrow><mi>s</mi><mi>y</mi><mi>m</mi></mrow></msub><mrow><mo>(</mo><mrow><msub><mi>G</mi><mn>1</mn></msub></mrow><mo>)</mo></mrow><mo>=</mo><msub><mi mathvariant="sans-serif">Ω</mi><mrow><mi>s</mi><mi>y</mi><mi>m</mi></mrow></msub><mrow><mo>(</mo><mrow><msub><mi>G</mi><mn>1</mn></msub></mrow><mo>)</mo></mrow><mo>=</mo><mn>0</mn></mrow></semantics></math></inline-formula> for the patterns built of irregular, non-symmetric shapes, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>G</mi><mn>1</mn></msub></mrow></semantics></math></inline-formula> is the identity element of the symmetry group. Both informational measures of symmetry are intensive parameters of the pattern and do not depend on the number of shapes, their size, and the entire area of the pattern. They are also insensitive to the long-range order (translational symmetry) inherent for the pattern. Additionally, informational measures of symmetry of fractal patterns are addressed, the mixed patterns including curves and shapes are considered, the time evolution of Shannon measures of symmetry are examined, the close-packed and dispersed 2D patterns are analyzed, and an application of the suggested measures of symmetry for the analysis of the chemical reaction is demonstrated.
Propellant Gauging is of vital importance to a spacecraft at the end of its life. Based on the Monte Carlo Method, uncertainty analysis and the improvement of propellant gauging using gas injection have been studied. As a result of the analysis, the gauging uncertainty has weak relation to the uncertainties of the volumes of the injection room and tank, the uncertainties of the pressure, and the temperature in the injection room. Relatively, the uncertainties of the temperature and pressure in the tank have a great effect on the gauging uncertainty. By improving the uncertainties of the tank pressure and temperature within 0.04% and 0.4%, the final gauging uncertainty can be obtained within 0.4%. Ground tests have been conducted and the results came out with approximately 0.4% error, well within the theoretical analysis.
Control of the disturbed displacement of adjacent tunnel during excavation is a significant issue for design and construction. Based on the multi-objective optimization method, the multi-type monitoring data in the excavation of the excavation are integrated, the key soil parameters are inverted and identified, and the time effect of the tunnel displacement is quantified and corrected. A dynamic multi-objective optimization method with adaptive infill criterion (DMO-AIC) is proposed to improve the updating efficiency of dynamic surrogate models. The proposed method takes into account the computational redundancy of dynamic surrogate models in engineering optimization, and designs an adaptive point-adding discrimination strategy, which can autonomously identify invalid updates of surrogate models on the optimization path. The results show that the proposed DMO-AIC significantly reduces the invocations of the black-box model during optimization while ensuring the good search performance and the convergence speed of the algorithm. The improved computational efficiency of DMO-AIC is helpful for the application of dynamic surrogate models in engineering optimization. The results of the virtual numerical example show that DMO-AIC can predict and update multiple model responses during excavation, such as wall deflections and tunnel displacements. The engineering practice of Shanghai Bund 596 excavation indicates that the time effect is properly updated, and the staged vertical displacements of the adjacent tunnel are accurately predicted.
Engineering (General). Civil engineering (General), Chemical engineering
Several studies have shown that Illumina MiSeq high-throughput sequencing can be used to measure the diversity of prokaryotes and fungal communities that provide ecosystem functions in agricultural soils. Pedoclimatic properties of soils, together with cropping systems and agricultural management practices, are major drivers of soil microbiome diversity. Their effects must be quantified and compared to technical variability to improve the relevance of observed effects and the indicators that may result from them. This study was conducted: 1) To assess the effects of three sources of technical variability on the soil prokaryotes and fungal diversity; 2) To identify a source of technical variability that can be used as a threshold to better assess crop management effects; 3) To evaluate the effects of spatial and temporal variability compare to a technical threshold in three crop management contexts, potato, corn/soybean and grassland. Technical variability was evaluated in a basis of sampling, soil DNA extraction and amplicon sequencing source of variability. Spatial variability was evaluated using composite bulk soil cores at four sampling points covering 2500 m² per field. Geolocated soils were also collected on three sampling dates during the growing season to evaluate temporal variability. A technical variability threshold was determined for the soil DNA extraction variability with a delta of Shannon index of 0.142 and 0.390 and a weighted UniFrac distance of 0.081 and 0.364 for prokaryotes and fungi, respectively. We observed that technical variability was consistently similar or lower than the spatial and temporal variabilities in each of the microbial communities. Observed variability was greater for the diversity of fungi and the crop system has a strong effect on temporal and spatial variability.
Chemistry, Engineering geology. Rock mechanics. Soil mechanics. Underground construction
Mariane Peripolli, Sylvio H. B. Dornelles, Sidinei J. Lopes
et al.
ABSTRACT The objective of this study was to evaluate the effect of the application of the biostimulants Seed+ and Crop+ on physiological and production variables and on the activity of antioxidant enzymes (superoxide dismutase - SOD and guaiacol peroxidase - POD) in tomato plants subjected to two soil water conditions. The experiment was carried out in a greenhouse, in a 2 x 2 x 6 factorial scheme, with two times of application of the biostimulants (flowering and fruiting), two soil water conditions (50 and 100% of soil water holding capacity) and six biostimulants (control treatment; Seed+; Seed+ + Crop+ 1x; Seed+ + Crop+ 2x; Crop+ 1x; + Crop+ 2x). The exprimental design was completely randomized, with four repetitions. The biostimulants Seed+ and Crop+ increased the quantum yield of photosystem II (Fv/Fm), regardless of the time of application and water condition of the soil. The biostimulants Seed+ + Crop+ 2x and Crop+ 2x stood out in the pre-morning period, with an average Fv/Fm of 0.813, under the conditions tested. The highest SOD activity (372.12 U mg-1 of protein) was obtained with Crop+ 2x biostimulant in fruiting and under water deficit. For POD, when under water deficit, the best results were obtained with the biostimulants Seed+ + Crop+ 2x, Crop+ 1x and Crop+ 2x in flowering (810.94; 691.19 and 921.59 U mg-1 protein) and in fruiting (703.60; 800.00 and 972.62 U mg-1 protein). Thus, the use of Seed+ and Crop+ biostimulants can be an alternative to help mitigate the damage caused by water deficit in tomato crop.
Study of swinging clapper bells involves aspects encompassing sound and acoustic engineering, mechanical engineering, and structural engineering. From the musical point of view, clapper bells are directly played idiophone instruments, where the playing device, the clapper, although directly excited, is not explicitly controlled by the bell ringer. The achievement of a clear and optimal sound mainly depends on the acoustic characteristics of the bell and on the regularity of the clapper strokes, which is not only governed by the ringing style and the relevant parameters of clapper and bell but also by the real time corrections to the excitation introduced by trained bell ringers. In fact, despite centuries of experience allowed to optimize the bell performances, standardizing proportions and mounting arrangements, effective sound control requires some fine tuning of the forcing function. Another crucial topic, especially in view of assessing existing structures, regards the evaluation of time histories of the actions transmitted by the bell to the pivots and the study of the interactions between the bell and the supporting structures, belfries, and bell-towers. “Ringability” of swinging bells and bell-structure interactions are usually tackled in the framework of rigid body dynamics, so arriving at an initial value problem, governed by a system of two second order nonlinear ordinary differential equations (ODEs), whose solutions are piecewise-defined functions. In the relevant literature, numerical solutions of the system are commonly sought using built-in algorithms provided in advanced software packages; since the use of such general algorithms is subject to some restrictions, especially regarding the forcing functions, validity of the results is often limited. The present study focuses on an innovative procedure to solve the equations of motion. The method, extremely fast and effective, is based on original numerical explicit-implicit predictor-corrector integration algorithms with constant time step, duly validated reproducing the outcomes of relevant reference case studies. Each time the clapper strikes the bell a new “piece” of the solution is initialized, so avoiding user interventions in the elaboration phase. Independently on the oscillation amplitude and on the duration of the considered time interval, the algorithms can successfully manage undamped oscillations; friction and viscosity damped oscillations; free oscillations in transient and stationary phases; and can be applied also to solve stiff equations. Furthermore, the capability of the proposed methods to deal with arbitrary forcing functions is particularly innovative. The outcomes of relevant case studies, regarding the oscillations of the old tenor bell of the Great St. Mary church in Cambridge, confirm the potentialities of the method, also highlighting some topical issues, involving, for example, the assessment of damping equivalence. Finally, a pioneering feature of the algorithms is their ability to handle and to define “resonant” forcing functions, continuously tuning the frequency of the excitation to the natural frequency of the oscillation, according to the oscillation amplitude.
The filtering and polarizing of terahertz waves are essential for various terahertz applications. Here, we use two-dimensional (2-D) rectangular subwavelength hole arrays (SHAs) to achieve efficient wave filtering and polarizing in the terahertz region. The transmissive filtering is obtained by exciting the specified resonant modes within the subwavelength holes. With the same basic physics, the elliptic-to-linear and linear-to-elliptic (linear-to-circular) polarization conversions are successfully achieved by properly arranging the 2-D SHAs. Thanks to its easy realizability, these 2-D SHAs can promisingly be developed as efficient terahertz wave filters and polarizers for practices.