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We discuss the nonlinear process of optical parametric amplification inside a chiral crystal. We show that circular birefringence, induced by chirality, leads to two different nonlinear processes with different phase-matching conditions that are associated with the opposite states of circular polarizations. A single nonlinear process occurs only when the states of polarization of the incident pump and signal beams are both circular and orthogonal. When these beams are linearly polarized initially, their state of polarization evolves in an elliptical fashion because of the two competing nonlinear processes taking place in parallel. We also discuss the properties of singly and doubly resonant optical parametric oscillators made by placing a chiral nonlinear crystal inside an optical cavity. [ABSTRACT FROM AUTHOR]

This paper reports the mass and energy transmission characteristics of an electrically conducting mixed convective nanofluid flow past a stretching Riga plate. An additional effect of viscous dissipation, Arrhenius activation energy and heat source is also studied. The energy and mass transmissions are evaluated by a zero-mass flux of nanoparticle and convective boundary conditions. Buongiorno's relations are proposed for the Brownian motion and thermophoretic diffusion. The similarity substitutions are employed to derive the non-dimensional set of modeled equations. The obtained set of equations is numerically processed via parametric continuation method (PCM). Several flow factors affecting the velocity, energy, and mass distributions are graphically discussed. It has been perceived that the fluid velocity field declines with the influence of velocity power index (m), while improves with the upshot of modified Hartmann number (Q). The effect of Schmidt number and chemical reaction diminishes the concentration profile φ (η). Furthermore, the energy curve enhances with the effect of thermophoresis factor, Biot and Eckert number. [ABSTRACT FROM AUTHOR]

In-situ consolidation of thermoplastic composites using Automated Fibre Placement (AFP) technology is an emerging manufacturing technique, offering tailored composite properties through customised processing parameters. Multiple competing parameters during AFP manufacturing influence the quality and mechanical performance of the laminates. These lay-up parameters are interrelated, and often require comprehensive experimental characterisation which is costly and time-intensive. This study aims to optimise the fracture toughness of in-situ consolidated thermoplastic composite (AS4/APC-2) and investigate the mechanisms that contribute to it. Taguchi's method is employed to efficiently analyse the effect of various process parameters at multiple levels. Based on the obtained results, a considerable effect of process parameters on Mode I and II fracture toughness is observed. The statistical analysis reveals that the Hot Gas Torch (HGT) temperature required for AFP processing significantly affects the Mode I fracture toughness, contributing to 33.8%. Whereas, the consolidation force, another key processing parameter in AFP notably affects Mode II fracture toughness, with the contribution of 81.8%. The analysis of variance (ANOVA) reveals interdependent processing parameter relations for both fracture modes. A validation test showed good agreement between the predicted fracture toughness and the experimental test. [ABSTRACT FROM AUTHOR]

Purpose: To provide lumbar spine anatomical parameters relevant to the UBE technique and explore their intraoperative application. Methods: CT imaging data processed by Mimics for parametric measurements, including laminar abduction angle (LAA), laminar slope angle (LSA), minimum laminar height (MLH), distance between the inferior margin of the lamina and attachment of the ligamentum flavum onto the cephalad lamina (DLL), distance between the initial point and the middle of the articular process (DIA), and distance from the inferior margin of the lamina to the inferior border of the vertebral body (DLV), and were manually measured. Results: LAA and DIA gradually increase from L1 to L5. At L1, the DIA is approximately the length of 2 drill bits with a diameter of 3 mm (male: 7.77 ± 1.39 mm, female: 7.22 ± 1.09 mm), while at L5, it can reach the length of 4–5 drill bits (male: 14.96 ± 2.24 mm, female: 13.67 ± 2.33 mm). MLH, DLL, and DLV reach their maximum values at the L3 and decrease toward the cranial and caudal ends. The DLL is smallest at L5 (male: 9.58 ± 1.90 mm, female: 9.38 ± 2.14 mm), equivalent to the length of 3 drill bits, while the DLL at L3 is the length of 4–5 drill bits (male: 14.17 ± 2.13 mm, female: 14.01 ± 2.07 mm). Conclusion: Referring to the drill diameter during surgery can mark the extent of laminotomy. The characteristics of vertebral plate angles at different lumbar levels can provide references for preoperative incision design. [ABSTRACT FROM AUTHOR]

AbstractWe present parametric and semiparametric latent Markov time-interaction processes, that are point processes where the occurrence of an event can increase or reduce the probability of future events. We first present time-interaction processes with parametric and nonparametric baselines, then we let model parameters be modulated by a discrete state continuous time latent Markov process. Posterior inference is based on a novel and efficient data augmentation approach in the Markov Chain Monte Carlo framework. We illustrate with a simulation study; and an original application to terrorist attacks in Europe in the period 2001-2017, where we find two distinct latent clusters for the hazard of occurrence of terrorist events, negative association with GDP growth, and self-exciting phenomena. [ABSTRACT FROM AUTHOR]

Three‐dimensional visualisation of mesh reconstruction of the medical images is commonly used for various clinical applications including pre / post‐surgical planning. Such meshes are conventionally generated by extracting the surface from volumetric segmentation masks. Therefore, they have inherent limitations of staircase artefacts due to their anisotropic voxel dimensions. The time‐consuming process for manual refinement to remove artefacts and/or the isolated regions further adds to these limitations. Methods for directly generating meshes from volumetric data by template deformation are often limited to simple topological structures, and methods that use implicit functions for continuous surfaces, do not achieve the level of mesh reconstruction accuracy when compared to segmentation‐based methods. In this study, we address these limitations by combining the implicit function representation with a multi‐level deep learning architecture. We introduce a novel multi‐level local feature sampling component which leverages the spatial features for the implicit function regression to enhance the segmentation result. We further introduce a shape boundary estimator that accelerates the explicit mesh reconstruction by minimising the number of the signed distance queries during model inference. The result is a multi‐level deep learning network that directly regresses the implicit function from medical image volumes to a continuous surface model, which can be used for mesh reconstruction from arbitrary high volume resolution to minimise staircase artefacts. We evaluated our method using pelvic computed tomography (CT) dataset from two public sources with varying z‐axis resolutions. We show that our method minimised the staircase artefacts while achieving comparable results in surface accuracy when compared to the state‐of‐the‐art segmentation algorithms. Furthermore, our method was 9 times faster in volume reconstruction than comparable implicit shape representation networks. [ABSTRACT FROM AUTHOR]

Multivariate statistical process control (MSPC) charts are particularly useful when there is a need to simultaneously monitor several quality characteristics of a process. Most of the control charts in MSPC assume that the quality characteristics follow some parametric multivariate distribution, such as the normal. This assumption is almost impossible to be justified in practice. Distribution-free MSPC charts are attractive, as they can overcome this hurdle by guaranteeing a stable (or in-control (IC)) performance of the control chart without the assumption of a parametric multivariate process distribution. Utilizing an existing distribution-free multivariate tolerance interval, we propose a Phase II Shewhart-type distribution-free MSPC chart for individual observations, with control limits based on Phase I order statistics. In addition to being easy to interpret, the proposed chart preserves the original scale of measurements and can easily identify out-of-control variables after a signal. The exact in-control performance based on the conditional and unconditional perspectives is presented and examined along with the control limits determination. The out-of-control performance of the chart is studied by simulation for data from a number of multivariate distributions. Illustrative examples are provided for chart implementation, using both real and simulated data, along with a summary and conclusions. [ABSTRACT FROM AUTHOR]

Intense long‐wave infrared (LWIR) femtosecond pulses within the 8−14 µm atmospheric window present an array of applications, such as in strong‐field physics, ultrafast nonlinear spectroscopy, and self‐guided atmospheric propagation. However, the realization of an LWIR source capable of delivering millijoule‐class energy, few‐cycle duration, and kHz repetition rate concurrently remains challenging. Here, such an LWIR source via the combination of different nonlinear parametric processes is reported, driven by a 1 kHz Yb:YAG thin‐disk laser. The system comprises two parallel multi‐cycle optical parametric chirped‐pulse amplifiers (OPCPAs) operating at 2.3 and 3.1 µm, respectively, alongside a stage of ZnGeP2‐crystal‐based difference‐frequency generation (DFG). The resulting 9 µm DFG pulses have a record energy of 0.21 mJ, a 3‐cycle duration, a 1 kHz repetition rate, and long‐term energy stability. The simultaneous output of three synchronized intense lasers at short‐wave infrared (2.3 µm), mid‐wave infrared (3.1 µm), and LWIR (9 µm) renders the source particularly appealing for multicolor ultrafast applications. [ABSTRACT FROM AUTHOR]

Recently, the agriconstruction machinery sector has been involved in a great technological revolution. The reasons that may explain this are strictly connected to the mitigation of climate change. At the same time, there is a necessity to ensure an adequate production level in order to meet the increasing food demand due to the current population growth trend. In this context, the development of autonomously driven agricultural vehicles is one of the areas on which tractor manufacturers and academics are focusing. The fundamental prerequisite for an autonomous driving vehicle is the development of an appropriate motion strategy. Hence, the vehicle will be able to follow predetermined routes, accomplishing its missions. The aim of this study was the development of path-planning and path-following algorithms for an agricultural four-whee differential-drive vehicle operating in vineyard/orchard environments. The algorithms were completely developed within the MATLAB software environment. After a brief description of the geometrical characteristics of the vehicle, a parametric process to build a virtual orchard environment is proposed. Then, the functional principles of the autonomous driving algorithms are shown. Finally, the algorithms are tested, varying their main tuning parameters, and an indicator to quantify the algorithms' efficiency, named relative accuracy, is defined. The results obtained show the strong dependence between the relative accuracy and lookahead distance value assigned to the rover. Furthermore, an analysis of rover positioning errors was performed. The results in this case show a lower influence of the location error when the accuracy of the positioning device is within 2 cm. [ABSTRACT FROM AUTHOR]

This paper outlines the planning of a bridge in central Germany. Scheduled for construction in mid‐2024, this new bridge is a replacement for a century‐old pedestrian bridge crossing the Lahn river. The proposed bridge will be an airtight‐welded arch bridge, employing steel cross‐sections in both the arch and tension member. Designed as a single‐span, the arches extend 48.0m over the Lahn. The two arches have a flat rise of 4.65m, supporting the roadway through 9 inclined flat steel hangers. This paper delves into the structural engineering aspects, exploring challenges inherent in the design process. An examination of the parametric design process, facilitated through 3‐D modeling in Rhino® and Grasshopper®, will be presented, along with insights into their interface with the finite element modeling software, RFEM®. This process enables an engineering approach to form‐finding and structure optimisation through iterative design checks for various elements and stages of the structural analysis. [ABSTRACT FROM AUTHOR]

In the past two decades, number of studies have been reported on process parametric optimisation of the fused filament fabrication (FFF) process for polylactic acid-based functional prototypes by using design of experiment techniques. But hitherto little has been reported on the prediction of mechanical and surface properties of FFF prints using machine learning (ML) and a finite element analysis (FEA) approach. The present research work aims to provide insight into the influence of FFF parameters, namely: layer thickness (LT), infill structure (IS) and infill density (ID) on Young's modulus and surface roughness. In the first stage, optimum process parameters of FFF for Young's modulus and surface roughness have been evaluated as 0.16 mm LT, cubic IS and 45% ID along with an analysis of variance-based linear models. The ML-based computational model has been developed to predict and verify the experimental observations in the second stage. Finally, in the third stage, experimental and predicted values of Young's modulus have been co-related based upon FEA (by using ABAQUS software). [ABSTRACT FROM AUTHOR]

AbstractStatistical modeling of a nonstationary spatial extremal dependence structure is challenging. Parametric max-stable processes (MSPs) are common choices for modeling spatially indexed block maxima, where an assumption of stationarity is usual to make inference feasible. However, this assumption is unrealistic for data observed over a large or complex domain. We develop a computationally efficient method for estimating extremal dependence using a globally nonstationary but locally stationary MSP construction, with the spatial domain divided into a fine grid of subregions, each with its own dependence parameters. We use LASSO (L1) or ridge (L2) penalties to obtain spatially smooth parameter estimates. We then develop a novel data-driven algorithm to merge homogeneous neighboring subregions. The algorithm facilitates model parsimony and interpretability. To make our model suitable for high-dimensional data, we exploit a pairwise likelihood to perform inference and discuss its computational and statistical efficiency. We apply our proposed method to model monthly maximum temperature data at over 1400 sites in Nepal and the surrounding Himalayan and sub-Himalayan regions; we show significant improvements in model fit compared to a stationary model. Furthermore, we demonstrate that the estimated merged partition is interpretable from a geographic perspective and leads to better model diagnostics by adequately reducing the number of parameters. [ABSTRACT FROM AUTHOR]

A new coefficient of variation (CV) functionally adaptive exponentially weighted moving average control chart is presented by considering the influence of the measurement error (ME) and named the "FAEWMA-ME-CV" control chart. The linear covariate model and the multiple measurements method are used to present the control chart. The designed function is efficient to detect the infrequent process changes in the form of parametric shifts in the process CV. The proficiency of the design is evaluated by analyzing the run-length values which are determined by the Monte Carlo simulation runs shown for the various parametric settings in extensive tables. The analysis depicts that the presence of the ME plays a significant role in the performance of a control chart. Moreover, a real-life dataset explained the application of the proposed FAEWMA-ME-CV chart to support the argument. [ABSTRACT FROM AUTHOR]

A polymer valve seat is an essential component of ball valves. However, a gas pipeline valve leakage during the gas or oil transportation process causes major issues. Therefore, the fine finishing of the polymer valve seat is important. This work describes the effect of the magnetorheological finishing (MRF) process on the surface characteristics of the polymer valve seat. To achieve a finely finished polymer valve seat surface, the best process parametric combination of current, workpiece rotational, and tool rotational speed are obtained using the response surface methodology. The optimum process parameters are further used to enhance surface characteristics (including surface roughness, microhardness, and surface morphology) through fine finishing. Using the optimum process conditions, the surface roughness was reduced to 110nm from 570nm in 140min of finishing on a 4878mm2 surface area of the polymer valve seat. The circularity of the valve seat surface’s dimensional correctness is investigated further. The current MRF process can fine-finish the polymer valve seat surface consistently, resulting in improved surface characteristics and functional performance. [ABSTRACT FROM AUTHOR]

In many different manufacturing techniques, additive manufacturing technologies have proven to be quite useful for developing a prototype model in wide range of applications. In that technique, Fused Deposition Modeling (FDM) is one of the concern favorite methods used in industries, because it can create complex structures at a low cost. FDM uses the polymer ingredients that are melted, extruded, and layered on top of one another to create the desired product, independent of design intricacy. This examination analyzes the effects of several process variables on the flexural and impact characteristics of parts produced of polyethylene terephthalate glycol (PETG)material, including infill structure, layer thinness, infill multi-layering, and infill concentration. The L9 orthogonal array was developed by the Taguchi method to be employed in this design of experiment. Through the analysis of variance (ANOVA), the study elucidated the relative substance and percentage effort of each process parametric quantity to the desired outcomes. The results obtained through the Taguchi method revealed optimal parameters for both impact strength and flexural tests. For impact strength, the optimum factor was determined as a layer thinness of 0.12-millimeter, quarter cubic infill structure, 30% infill denseness (density), and a multi-layering of 3. Conversely, for the flexural test, the optimal factor was found to be a layer thinness of 0.12-millimeter, cross 3D infill structure, 60% infill denseness, and a multi-layering of 4 respectively. [ABSTRACT FROM AUTHOR]

Integrated Raman microlasers, particularly discrete multi‐color lasers which are crucial for extending the emission wavelength range of chip‐scale laser sources to much shorter wavelengths, are highly in demand for various spectroscopy, microscopy analysis, and biological detection applications. However, integrated multi‐color Raman microlasers have yet to be demonstrated because of the requirement of high‐Q microresonators possessing large χ(2) nonlinearity, strong Raman phonon branches, and the challenge in the cavity‐enhanced multi‐photon hyper‐Raman scattering parametric process. In this work, integrated multi‐color Raman lasers have been demonstrated for the first time at weak pump levels, via the excitation of high‐Q (> 6 × 106) phase‐matched modes in single thin‐film lithium niobate (TFLN) microresonators by dispersion engineering. Raman lasing is observed at 1712 nm for a 1547‐nm pump threshold power of only 620 µW, representing the state of the art in the TFLN platform. Furthermore, multi‐color Raman lasers are realized at discrete wavelengths of 1712, 813, 533, and 406 nm with pump levels as low as 1.60 mW, which is more than two orders of magnitude lower than the current records (i.e., 200 mW) in bulk resonators, allowed by the fulfillment of the requisite conditions consisting of broadband natural phase match, multiple‐resonance, and high‐Q factors. [ABSTRACT FROM AUTHOR]

Hybrid titanium metal matrix composites (HTMMCs) are advanced composite materials that can be tailored to a variety of applications. Because of their decreased fuel consumption and cost, they are popular in the transportation industry. Using multi-objective optimization and Taguchi-based Grey relational analysis (TGRA), this study investigates the impact of hybrid reinforced HTMMCs synthesized using powder metallurgy on their physic mechanical properties. The research investigates reinforcements such as B4C, SiC, ZrO2, and MoS2 at various compaction pressures, milling durations, and sintering temperatures. The best powder metallurgy control parameters for HTMMC synthesis, with a milling time of 5 h, a compaction pressure of 40 MPa, a sintering temperature of 1200 °C, and a sintering time of 1 h, and a compaction time of 40 min. According to validation results, HTMMC material with optimized process parameters had experimental densities, porosities, hardness, compressive strength, and wear rates of 4.29 gm/cm3, 0.1178%, 71.53RHN, 2782.36 MPa, and 0.1519 mm3 correspondingly. The material hardness was increased by 1.99% and compressive strength by 2.87%. The use of Taguchi and GRA techniques strongly verified that the impact of milling duration and sintering temperature was the greatest of all five factors. The novel synthesized hybrid reinforcing HTMMCs outperformed pure Ti grade 5 and single and double fortified HTMMCs in terms of physic mechanical characteristics. As a result, the newly developed tetra hybrid reinforced HTMMC material is expected to be used in heavy-duty vehicles, aerospace, automobiles, maritime, and other industries. Highlights: Developed new HTMMCs engineering material using powder metallurgy. In a multi-response optimization process, Taguchi-based Grey relational analysis (TGRA) was used to determine the most effective combinations of process variables. The high relative density, robust interface, and minimal cavities/porosity (less than 1%) of the sintered specimens make them acceptable engineering materials for use in the automotive and aerospace industries. The optimized HTMMC material exhibited improved hardness and compressive strength examination results, with an improvement of 1.99% in hardness and 2.87% in compressive strength. [ABSTRACT FROM AUTHOR]

Yttria-stabilized zirconia (YSZ) with a yttria content beyond 8%mol is especially interesting for its high ionic conductivity in the high-temperature range (700–1000 °C). Thereby, cubic YSZ properties make it a useful ceramic material for electrodes or electrolytes in various applications, such as solid oxide cell (SOC) technologies for energy conversion or oxygen sensors. This work aims to propose an alternative microstructure, hopefully, to improve material features. Adapting a sol–gel-type process that involves the use of supercritical CO2 (scCO2) to stabilize doped-zirconia nanoparticles in their cubic structure allows the crystallization of powders at temperatures as low as 250 °C. The resulting powders are very fine, with large specific surface areas around 50–150 m2 g−1, low agglomeration, and small-sized crystallites around 8–10 nm. After studying the effect of the operating conditions on the stabilization of the cubic crystalline phase, a well-adapted powder was selected and characterized in detail with respect to its microstructure, and its thermal behavior was investigated to eventually prepare an electrode/electrolyte. [ABSTRACT FROM AUTHOR]

In the last two decades, several studies have been conducted for the process parametric optimization of fused filament fabrication (FFF) with a variety of thermoplastic composites, especially for mechanical properties. But hitherto less has been conveyed, on the development of dynamic reduced order models (ROMs) for digital twining (DT) of tensile properties (of 3D printed implants/scaffolds) with novel thermoplastic-based composites. In this study, for the generation of dynamic ROM (for hybrid analytics), the signal-to-noise (S/N) ratio was used to ascertain the best settings of parameters for tensile properties of polyvinylidene fluoride (PVDF) composite. The study suggests that the best setting of the FFF process, for the 3D printing of PVDF composite (90% PVDF, 8% hydroxyapatite (HAp), and 2% Chitosan (CS) (for maximizing the tensile properties as per ASTM-D638-Type-V) are nozzle temperature (NT) of 235°C, raster angle (RA) 45°, printing speed (PS) of 60 mm/s respectively resulting in peak load (PL) 394.87 N, peak stress (PSt) 33.92 MPa, Young's modulus (E) 2.606 MPa. For a modulus of toughness (MOT) of 0.484 MPa, the best settings are NT 230°C, RA 90°, and PS 50 mm/s. The results are supported by the morphological analysis. [ABSTRACT FROM AUTHOR]

Radiation-initiated cross-linking polymerization of multifunctional monomers is an attractive method used for drying solvent-free liquid coatings, inks, and adhesive as well as for fabricating high-performance composite materials. The method offers a number of advantages compared with thermal curing processes. Free radical and cationic polymerization have been investigated in detail over the past years. A high degree of control over curing kinetics and material properties can be exerted by adjusting the composition of matrix precursors and/or by acting on the process parameters (overall dose, dose rate, dose increment, initial temperature). Several pending issues that require deeper investigations are as follows: (i) the fast polymerization of multifunctional monomers generates micro-heterogeneous networks requiring detailed characterization and quantification by microscopic, thermal, and spectroscopic analyses; (ii) the adhesion and surface properties of radiation-cured coatings are quite sensitive to processing parameters; and (iii) significant enhancement of the toughness is needed to qualify potential matrices based on simple difunctional monomers for high-performance composites. Recent results show that the bulk and surface properties of radiation-cured materials can be improved by advanced formulation of matrix precursors and by a parametric study of the processing factors. [ABSTRACT FROM AUTHOR]

Based on the parametric oscillation process, we demonstrate the dual-axis phase-sensitive demodulation (PSD) and single-axis phase-insensitive demodulation (PISD) for the atomic magnetometer in an in situ nuclear magnetic resonance (NMR) detection system, which can separate the precession signals of NMR from the oscillating magnetic fields. The two orthogonal magnetic fields can be detected simultaneously and independently by selecting the optimal demodulation phases with the traditional PSD method. The response signals of the parametric modulation magnetometer demodulated with high order harmonic signals are evaluated, which is a new exploration. The first order harmonic demodulation can present the best sensitivity about 250 fT/Hz1/2. The high order harmonic demodulation technology supplies a twofold 3 dB bandwidth. With the PISD method, a single-axis demodulation technique is proposed. The transverse nuclear spin precession magnetic fields can be extracted effectively with the demodulation R signal outputs by setting a specific longitudinal modulation magnetic field amplitude, which is a new demodulation strategy compared with the traditional demodulation method for the NMR system. [ABSTRACT FROM AUTHOR]

In this study, we introduce an innovative semiconductor quantum well (SQW) nanostructure, which exhibits a unique four-level configuration arranged in an inverted Y-shape. This configuration enables interaction with three laser fields and demonstrates the intriguing nonlinear phenomenon of parametric generation. Our investigation delves into a wide range of parametric conditions, aiming to understand the profound impact of various system parameters on the generation and propagation of new light fields within this groundbreaking nanostructure. By employing a combination of analytical and numerical methods, we not only reveal the potential for precise manipulation of coherence among energy levels but also showcase its practical implications — high-efficiency and tunability in the parametric generation process. This pioneering scheme represents a significant advancement in the field of SQW structures, bridging the gap between theoretical exploration and practical application. Our findings promise exciting prospects for the development of novel light sources and optical devices based on SQW structures, thereby pushing the boundaries of what is achievable in various applications and setting new standards for the state-of-the-art in this domain. [ABSTRACT FROM AUTHOR]

The manufacturing process parameters play a critical role in determining the quality of resin‐matrix composite structures. This study aims to investigate the impact of process parameters on void content and identify the stable and minimal void content of nano‐reinforced filament‐wound risers. Fourteen process parameters were initially designed, taking into account winding tension, speed, and curing time, based on the Box–Behnken design method. Subsequently, a void content model was developed using the response surface method, utilizing experimental data. The study further explores the effects of individual and combined process parameters on void content and establishes a stable process window through sensitivity analysis. Finally, the PSO‐GWO algorithm is employed to optimize winding tension, speed, and curing time with the objective of reducing void content. The results of the numerical analysis highlight the significant influence of curing time on void content, and the optimal parametric combination is determined to be 48.4 N winding tension, 12.6 m/min winding speed, and 6.7 h of curing time. Highlights: Winding tension and rate have a similar impact on porosity content.Void content sensitivity to tension is affected by feed rate and curing time.The stable process windows are winding tension [28 N, 53 N], feed rate [30%, 78%], and curing time [5.1 h, 8.4 h].The optimal parameters combination is 48.4 N, 63%, and 6.7 h. [ABSTRACT FROM AUTHOR]

Using the Lie-algebraic approach, we develop the theory of generation of squeezed states of light in nonstationary parametric processes of the light interaction with a medium with the quadratic and quartic nonlinearities. The exact solution for the variance of the quadrature component of the field strength is obtained in the case of the quadratic parametric process with the SU(1, 1) dynamical symmetry. We show that decay of the field mode in this processes may have strong impact on squeezing. The solution for the standard deviation of the field strength in the case of the quartic parametric process with the approximated L 5 dynamical symmetry is obtained in the first order of smallness with respect to the nonlinearity parameter. [ABSTRACT FROM AUTHOR]

We trained a long short-term memory (LSTM) network based on a pooled dataset made of hundreds of liquid stocks aiming to forecast the next daily realized volatility for all stocks. Showing the consistent outperformance of this universal LSTM relative to other asset-specific parametric models, we uncovered nonparametric evidence of a universal volatility formation mechanism across assets relating past market realizations, including daily returns and volatilities, to current volatilities. A parsimonious parametric forecasting device combining the rough fractional stochastic volatility and quadratic rough Heston models with fixed parameters resulted in the same level of performance as the universal LSTM, which confirmed the universality of the volatility formation process from a parametric perspective. [ABSTRACT FROM AUTHOR]

This paper introduces a dedicated algorithm for the automatic generation of water distribution network (WDN) layouts in EPANET, utilizing exclusively the street layout information contained in CAD files. The methodology involves reading and converting all elements constituting street boundaries into lines, which are then mathematically processed through parametric equations of lines. Subsequently, the central street lines are extracted and extended to generate intersection points. These points are then employed to define the network nodes, and, upon verifying connectivity among them, the pipes are automatically generated. The model's efficacy was evaluated on two distinct street layouts, and for both, the algorithm exhibited satisfactory results, automatically generating 100% of the network layout in EPANET input file. The model demonstrated swift performance for the considered layouts, with an average execution time of only 0.30 s. Furthermore, a comparison was conducted with the results obtained by the model proposed by Costa and Rodrigues (Water Resour Manage 35:1299–1319, 2021), with the performance of the model proposed in this work proving superior in both layout quality and computational time. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites (AMCs) developed with micro/nano-reinforcements emerge as an attractive candidate for innumerable applications, including automotive, aerospace, electronics, biomedical, and many more, owing to their high strength-to-weight ratio and outstanding tribological, mechanical, electrical, and thermal characteristics. This work aims to offer a review of the state of the art of research in the processing, fabrication, properties, and potential applications of AMCs. The review starts with an emphasis on light-weighted AMCs, followed by a brief discussion of the hybrid metal matrix composite structure and micro/nano-reinforcement. This review also includes an in-depth assessment of manufacturing processes and parametric factors that regulate the properties of AMCs. It also highlights the challenges that are currently encountered when processing AMCs, such as limited wettability, reinforcement agglomeration, and interfacial reactions, before analyzing the effect of adding micro/nano-reinforcements on the attributes of AMCs. In addition to the stated characteristics, the most feasible and novel applications of AMCs have been envisioned. Lastly, new research directions in the field of AMCs have been recommended and critically discussed. [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM) is a popular additive manufacturing technique, but attaining optimal processing variables continues to be a significant challenge. The design of experiments (DOE) method is used in this work to explore the effect of processing factors on the mechanical characteristics of metal-polymer composites generated by FDM, with a particular focus on adhesion. Filling quantity, extruded temperatures, raster orientation, and film thickness are considered fundamental design factors in the study, which employs Taguchi optimization methodology and Analysis of Variance (ANOVA) to investigate the relationship between processing variables, and tensile characteristics, such as ultimate tensile strength, yield strength, Young's modulus, ductility, and elongation at fracture. Tensile strength improved by 57% and yield strength increased by 85% when 20% aluminium was added to polylactic acid (PLA). It was also discovered that the ductility decreased with each incremental addition of aluminium to PLA. The tension investigation tests were carried out in line with ASTM D638-10. The results suggest that optimizing processing factors, such as 100% filling amount, 220 °C extruded temperature, 90° raster orientation, and 0.1 mm film thickness may greatly improve adhesion in FDM-fabricated metal-polymer composites. [ABSTRACT FROM AUTHOR]

Electrocoagulation (EC) is a well‐recognized and feasible treatment technique for wastewater treatment. The process optimization and analysis of process parameters of EC not only aid to scale up the EC process at an industrial level but also help to explore the economic and environmental considerations to achieve higher efficiency. Response surface methodology (RSM) is a prominent chemometric approach for both process optimization and evaluation of different factors for the removal of target pollutants from wastewater. This review provides a thorough examination of notable scholarly works that focus on the use of the RSM in EC for the purpose of wastewater treatment. Furthermore, the current advancements in implementing the RSM approach not only for standalone EC processes but also for the case are described where it is being practiced as a part in the integrating system for wastewater treatment. [ABSTRACT FROM AUTHOR]

The short de Broglie wavelength and strong interaction empower free electrons to probe structures and excitations in materials and biomolecules. Recently, electron-photon interactions have enabled new optical manipulation schemes for electron beams. In this work, we demonstrate the interaction of electrons with nonlinear optical states inside a photonic chip–based microresonator. Optical parametric processes give rise to spatiotemporal pattern formation corresponding to coherent or incoherent optical frequency combs. We couple such “microcombs” to electron beams, demonstrate their fingerprints in the electron spectra, and achieve ultrafast temporal gating of the electron beam. Our work demonstrates the ability to access solitons inside an electron microscope and extends the use of microcombs to spatiotemporal control of electrons for imaging and spectroscopy. [ABSTRACT FROM AUTHOR]

Nonlinear optical materials are essential in areas such as nanophotonics, optical information processing, and biomedical imaging. However, nanomaterials employed for these diverse applications to date are efficient only for one type of nonlinear optical activity. Herein, the first multimodal nonlinear optically active class of nanomaterials based on lanthanide‐doped lithium niobate nanoparticles, which simultaneously exhibit unprecedentedly efficient second and third harmonic generation, as well as up‐conversion photoluminescence, is reported. These dielectric nanoparticles retain their high nonlinear optical conversion efficiency both as powder and as aqueous colloidal solution. The high stability also allows for the fabrication of optically active biocompatible micron‐sized fibers and polymer‐based 3D‐printable objects, as well as for fingerprint detection. Finally, the first 8‐bit coding platform purely based on multimodal nonlinear optical activity originating from different parametric and nonparametric processes is demonstrated, showcasing the technological potential of these materials for both anti‐counterfeiting and advanced optical information processing. [ABSTRACT FROM AUTHOR]

This work deals with the asymptotic properties of maximum likelihood estimators for semi-Markov processes with parametric sojourn time distributions. It is motivated by the comparison, via a two-sample test procedure, of the distribution of two panels of qualitative trajectories modeled by semi-Markov processes and observed over a random number of transitions. Considering first one panel of growing size, we derive, under classical conditions, the convergence in probability of the estimators of the transition probabilities and the parameters of the sojourn time distributions as well as their asymptotic normality. We then consider panels of semi-Markov processes drawn from two different populations and study two-sample tests based on likelihood ratio. We also introduce a two-sample Wald type test. The finite sample performances of the proposed two-sample tests are evaluated with a brief simulation study. • Likelihood Ratio and Wald type tests are derived for panels of semi-Markov processes. • The asymptotic distributions of the test statistics are studied for parametric sojourn time distributions. • Two-sample tests are proposed based on Likelihood Ratio and the Wald type approach. • The finite sample properties are evaluated with a simulation study. • The Wald type approach seems to be more effective than the Likelihood ratio test for finite samples. [ABSTRACT FROM AUTHOR]

The present work study the acidic pug leaching technique for U-extraction in addition to some associated valuable metals from a collected technological sample of ferruginous shale from Wadi Um Hamed, Um Bogma Formation, Abu Thor locality, southwestern Sinai, Egypt. A representative sample of the ore material was found to assay 9000, 700 and 4000 ppm of REEs, U and Cu, respectively, in addition to some major and minor oxides. Numerous steps were performed upon the studied sample to process parametric studies such as sulphuric acid concentration (50–150 kg/ton), curing time (0.5–5.0 h) and curing temperature (50–150°C) in order to find the optimum condition. Under the optimal conditions (150 kg/ton sulphuric acid for 4.0 h at 150°C), the first step involved Fe-removal as hydroxide from the pregnant leaching solution using pH adjustment method followed by U-recovery through sorption/desorption and precipitation steps with the help of Amberlite IRA-400-Cl (strongly basic anion exchange resin) via column method. In the third step, REEs- recovery from U-free effluent was investigated using oxalic acid precipitation process while Cu-recovery by precipitation as hydroxide with ammonia solution took place. Energy dispersive X-ray analysis performed on the different obtained precipitates showed successive recovery of all above mentioned elements. Finally, U-uptake data were subjected to kinetic modelling. The kinetics of leaching reaction followed shrinking core model with chemical reaction as controlling mechanism based on activation energy value. [ABSTRACT FROM AUTHOR]

Solar-driven water desalination is growing quickly, typically using other renewable energy sources. However, its efficiency is heavily reliant on design and process parameters. The aim of this study is to experimentally investigate the impact of various design and process parameters on the performance of single slope solar still. Thus, a homemade solar still has been fabricated using acrylic sheet with a basin area of 0.25 × 0.25 m2 to carry out the experiments in Vellore, India (latitude 12.9692° N and longitude 79.1559° E). Additionally, this solar still setup is investigated using different absorbing plates (copper plate and copper plate with black coating), various glass cover angles (15°, 30° and 45°) and changing the wind speed (3 m/s, 3.5 m/s and 4 m/s) with help of electric fan. Daily energy efficiency and productivity of water are compared for the same basin area with different design and process parameters. From the results, daily energy efficiency and water productivity are improved with the increase of glass cover angle and wind speed. It is found that the best combination is copper plate with black coating, glass cover angle of 45° and wind speed of 4 m/s. This exhibits 34.09% in daily energy efficiency and 2640 ml/m2 in productivity of water. After the desalination process, the primary ions (Na+, K+, Mg2+, and Ca2+) of seawater are significantly reduced and satisfy the requirement of WHO standards. Subsequentially, dye removal is effectively achieved in the proposed solar still. [ABSTRACT FROM AUTHOR]

The nonlinear properties of zinc germanium diphosphide (ZGP) crystals enable their applications in powerful mid-IR optical parametric oscillators and second-harmonic generators. This paper summarizes the mechanisms of the laser-induced damage (LID) of high-purity ZGP crystals under periodically pulsed nanosecond irradiation by a Ho3+:YAG laser at 2.1 μm. The ZGP samples were manufactured by "LOC" Ent., Tomsk, Russia, or the Harbin Institute of Technology, China. The impact of processing techniques and the post-growing methods for polishing and anti-reflective coatings on the LID threshold are discussed. The importance of the defect structure of the crystal lattice and the parameters of transparent coatings for increasing the LID threshold are also discussed. The impact of the test laser parameters on the LID threshold and the transient area near the LID threshold obtained using digital holography are analyzed. The influence of the pre-damage processes on the optical parametric oscillations is reported. Lastly, the prospects for improving ZGP crystals to further increase the LID threshold are discussed. [ABSTRACT FROM AUTHOR]

Metronidazole (MNZ) is an extensively used antibiotic against bacterial infections for humans and farm animals. Prevention of antibiotics discharge is essential to prevent adverse environmental and health impacts. A member of metal–organic frameworks, zeolite imidazole framework-67 with cobalt sulfate precursor (ZIF-67-SO4) and exceptional physio-chemical properties was prepared via room temperature precipitation to adsorb MNZ. The study framework was designed by Box–Behnken Design to evaluate the effect of pH, ZIF-67-SO4 dose, and contact time on adsorption efficiency. The polynomial model fitted the adsorption system indicated the optimal condition for 97% MNZ removal occurs at pH = 7, adsorbent dosage = 1 g/L, and mixing time = 60 min. The model also revealed that the removal increased with contact time and decreased at strong pH. Equilibrium and kinetic study also indicated the adsorption of MNZ followed the intra-particle diffusion model and the Langmuir isotherm model with a qmax = 63.03 mg/g. The insignificant loss in removal efficacy in use-reuse adsorption cycles reflected the practical viability of ZIF-67-SO4. [ABSTRACT FROM AUTHOR]

This paper presents an extended calibration procedure for mode accelerometers, which makes it possible to compare the accuracy of sensors of this type from different manufacturers. This comparison involves determining the upper bound on dynamic error for a given quality criterion, i.e., the integral square error and absolute error. Therefore, this article extends the standard calibration implemented in engineering practice using tests, providing a value for the upper bound on dynamic error as an additional parameter describing the accelerometer under consideration. This paper presents the theoretical basis for this type of solution, which is partly based on measurement data obtained from a standard calibration process and on the results of parametric identification. The charge mode accelerometer is considered here because this type of sensor is commonly used in the energy industry, as it can operate over a wide range of temperatures. The calculation results presented in this paper were obtained using MathCad 5.0 software, and the tests were carried out using an accelerometer of type 357B21. In the experimental part of this article (Results of Extended Calibration section), values for the upper bound of the dynamic error were determined for two error criteria and constrained simulation signals related to these errors. The impact of interference on the results of accelerometer tests was omitted in this paper. [ABSTRACT FROM AUTHOR]

Conical emission is a typical nonlinear phenomenon that occurs during the filamentation of femtosecond laser pulses in transparent media. In this work, the conical emission induced by two kinds of typical vortex beams (i.e., Laguerre–Gaussian (LG) and Bessel–Gaussian (BG) beams) in water is experimentally studied. By recording the light spots of different spectra components from the supercontinuum induced by the vortex beams, the characteristics of the conical emission induced by femtosecond vortex beams are studied. It is found that the spots of the supercontinuum induced by the two kinds of vortex beams differ greatly from each other. The spots of the supercontinuum induced by the BG beams are a set of concentric rings like a rainbow with a white center, while the white light spots in the case of the LG beams are circular white disks, which are different from the commonly observed white light spots. By measuring the maximum divergence angle, it is observed that the divergence angle increases with a decrease in the wavelength, while it is merely affected by the topological charge, which is explained by the formation mechanism of conical emission in terms of self-phase modulation. Based on the observed results, we discuss the transfer of optical angular momentum during the supercontinuum induced by the filamentation of femtosecond vortex beams. This work may help to better understand the transfer of optical angular momentum in non-optical parametric processes as well as the interaction of high-intensity pulses with matter. [ABSTRACT FROM AUTHOR]

The realization of compact and efficient broadband mid-infrared (MIR) lasers has enormous impacts in promoting MIR spectroscopy for various important applications. A number of well-designed waveguide platforms have been demonstrated for MIR supercontinuum and frequency comb generations based on cubic nonlinearities, but unfortunately third-order nonlinear response is inherently weak. Here, we propose and demonstrate for the first time a χ(2) micrometer waveguide platform based on birefringence phase matching for long-wavelength infrared (LWIR) laser generation with a high quantum efficiency. In a ZnGeP2-based waveguide platform, an octave-spanning spectrum covering 5–11 μm is generated through optical parametric generation (OPG). A quantum conversion efficiency of 74% as a new record in LWIR single-pass parametric processes is achieved. The threshold energy is measured as ~616 pJ, reduced by more than 1-order of magnitude as compared to those of MIR OPGs in bulk media. Our prototype micro-waveguide platform could be extended to other χ(2) birefringence crystals and trigger new frontiers of MIR integrated nonlinear photonics. A χ(2) nonlinear micro-waveguide platform is demonstrated based on the birefringence phase matching for simple and efficient long-wavelength infrared generation, which could trigger new frontiers of MIR integrated nonlinear photonics. [ABSTRACT FROM AUTHOR]

Hong–Ou–Mandel (HOM) interference, bunching of two indistinguishable photons on a balanced beam‐splitter, has emerged as a promising tool for quantum sensing. There is a need for wide spectral‐bandwidth photon pairs (for high‐resolution sensing) with high brightness (for fast sensing). Here, the generation of photon‐pairs with flexible spectral‐bandwidth even using single‐frequency, continuous‐wave diode laser enabling high‐precision, real‐time sensing is showed. Using 1‐mm‐long periodically‐poled KTP crystal, degenerate, photon‐pairs with spectral‐bandwidth of 163.42±1.68 nm are produced resulting in a HOM‐dip width of 4.01±0.04 μ$\umu$m to measure a displacement of 60 nm, and sufficiently high brightness to enable the measurement of vibrations with amplitude of 205 ± 0.75 nm and frequency of 8 Hz. Fisher‐information (FI) and maximum likelihood estimation enables optical delay measurements as small as 4.97 nm with precision (Cramér–Rao bound) and accuracy of 0.89 and 0.54 nm, respectively, therefore showing HOM sensing capability for real‐time, precision‐augmented, in‐field quantum sensing applications. [ABSTRACT FROM AUTHOR]

In this research, electrocoagulation-intensified peroxidation using an aluminum electrode was studied as a post-treatment method for poultry slaughterhouse wastewater (SWW) with 4 operational variables (pH, current density, contact time, and H2O2 dosage). Optimization was carried out using response surface methodology. Analysis of variance was used to analyze the experimental data, and a second-order model was created to test the effects of process parameters on treatment performance. The optimum conditions were chosen as follows: pH 5.83, 0.18 g/L H2O2 dosage, 58.60 min contact time, and current density of 4.21 mA/cm2. The compatibility of the predicted optimum conditions has been verified by experimental data. As a result of the experiments performed under optimum conditions, COD, TSS, and color removals were found to be 97.89%, 99.31%, and 98.56%, respectively. The difference between experimental and predicted values was found to be less than 0.86%. The final treated effluent met the discharge standards determined by the World Bank, EU, US, and Malaysian Department of Environment. Under optimum conditions, the cost of treating 1 cubic meter of SWW was calculated as 3.02 MYR ($ 0.68). [ABSTRACT FROM AUTHOR]

Interactions between oblique second mode and oblique waves at a high-speed boundary at Mach 4.5 are studied using linear stability theory, nonlinear parabolized stability equations (NPSE) and direct numerical simulation (DNS). Parametric analysis based on the NPSE suggests that the oblique second mode can amplify both the oblique first and second modes, with the former experiencing a higher amplification. Our analysis reveals that the mean-flow distortion and difference mode contribute to this enhancement, with the latter exerting a key influence through the parametric resonance process. Kinetic energy transfer analysis demonstrates that the oblique waves gain energy from the mean flow, rather than from the oblique second mode. Furthermore, we find that the mechanism underlying the interaction between a pair of second oblique waves and a single oblique wave is similar to that between an oblique second mode and an oblique wave, as the steady modes generated by the pair of oblique second modes have a limited impact on the oblique wave. Finally, DNS confirms the validity of two transition paths proposed in this study based on the NPSE results. The first path suggests that a pair of low-amplitude second oblique waves alone are insufficient to cause oblique breakdown, but the introduction of a pair of low-amplitude damping first oblique modes could lead to boundary layer breakdown. The second path involves the formation of a domino-like effect through the combination of different types of oblique waves with the appropriate parameters. These two nonlinear paths can lead to a fully developed turbulent boundary layer. [ABSTRACT FROM AUTHOR]

The objective of this study is to propose a method called the fuzzy technique for order preference by similarity to the ideal solution (F-TOPSIS) to select parameters of the wire electrical discharge machining (WEDM) process. Consequently, the parameters principally influencing the outputs of the WEDM process were identified and examined using the F-TOPSIS framework where the inputs of three decision makers, representing their opinions are incorporated into the analysis. The idea of parametric selection in a WEDM process is multicriteria-based when the production of nitinol-60 smart memory alloy (SMA) is critically considered. Current approaches of TOPSIS and analytic hierarchy process (AHP) evaluations to select the WEDM parameters fail because of the constraints of linguistic evaluations, but the use of F-TOPSIS crosses over the restriction to choose the best parameters in a WEDM process for nitinol-60 SMA. In this work, the experimental results obtained from published research were utilised to validate the proposed method. The validation of the suitability of F-TOPSIS, aided by the published work on the WEDM process, analysed the surface integrity of nitinol-60 SMA. From the five outputs, the closeness coefficients of the best and worst are found to be 0.7567 and 0.2838, respectively. This research aids the process engineer in optimising the outputs in the WEDM process, to select the best output. Hence, the research showcased how the WEDM process could select outputs efficiently, thus aiding process engineers to maintain the process to optimise parametric resource allocations and guarantee utmost productivity. [ABSTRACT FROM AUTHOR]

The study on the nonlinear optical responses arising from plasmonic nanoantennas, known as nonlinear plasmonics, has been massively investigated in recent years. Among the most basic nonlinear optical responses, second-harmonic generation (SHG) and multiphoton photoluminescence (MPL), two-photon photoluminescence in particular, has aroused extensive interests, due to their distinct properties of being ultrasensitive to the spatial symmetry and ultrafast response time of hot electrons. In this review, we give insights into fundamental roles dominating the radiations of such nonlinear optical processes and their recent research advances. Different from other reviews on nonlinear plasmonics, which mainly focused on parametric processes, this review pays equal attentions to the incoherent process of MPL. An in-depth description on the excitation and emission processes of MPL in accordance with recent studies is fully presented. By using the high 'symmetry rule' of SHG and ultrafast response time of MPL, advanced applications in surface enhanced spectroscopy, ultra-sensitive photodetector, biosensor and ultrafast laser pulses are highlighted in the end. [ABSTRACT FROM AUTHOR]

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Fast, high-fidelity operations between microwave resonators are an important tool for bosonic quantum computation and simulation with superconducting circuits. An attractive approach for implementing these operations is to couple these resonators via a nonlinear converter and actuate parametric processes with RF drives. It can be challenging to make these processes simultaneously fast and high fidelity, since this requires introducing strong drives without activating parasitic processes or introducing additional decoherence channels. We show that in addition to a careful management of drive frequencies and the spectrum of environmental noise, leveraging the inbuilt symmetries of the converter Hamiltonian can suppress unwanted nonlinear interactions, preventing converter-induced decoherence. We demonstrate these principles using a differentially-driven DC-SQUID as our converter, coupled to two high-Q microwave cavities. Using this architecture, we engineer a highly-coherent beamsplitter and fast (~100 ns) swaps between the cavities, limited primarily by their intrinsic single-photon loss. We characterize this beamsplitter in the cavities' joint single-photon subspace, and show that we can detect and post-select photon loss events to achieve a beamsplitter gate fidelity exceeding 99.98%, which to our knowledge far surpasses the current state of the art. The beamsplitter operation is a key component for quantum information processing, but implementations in superconducting circuit-QED usually introduce additional decoherence. Here, the authors exploit the symmetry within a SQUID, driven in a purely differential manner, to realise clean BS operations between two SC cavity modes. [ABSTRACT FROM AUTHOR]

To move up the circular economy hierarchy steel profiles should be reused instead of recycled. To efficiently utilise the limited availability of reclaimed steel elements in new structures, a different approach is required: form follows availability. This paper presents an algorithm for generating truss bridge designs using only reclaimed steel, which optimises material efficiency and avoids cut‐off waste. The algorithm does not require an initial design or a grid of possible positions like the commonly used ground structure method. Instead, it lets a truss geometry grow from start to end. The algorithm was developed using Python in Grasshopper, resulting in a user‐friendly parametric design process. By defining the width and span of a truss bridge and providing a stock of reclaimed elements, a solution cloud of locally optimal truss bridge designs in terms of capacity utilisation is generated, which comply to Eurocode provisions. An optimal design can be selected with given objectives, e.g. the lowest environmental impact. A case study showed that the developed growth method can lead to a truss with 63% less embodied carbon than conventionally designed new steel trusses and 17% less embodied carbon than optimised standard truss designs with retrofitted reclaimed steel elements. [ABSTRACT FROM AUTHOR]