Linear Parameter Research Articles

A nonlinear Filbert-like matrix with three free parameters: From linearity to nonlinearity

Abstract Filbert and Lilbert matrices are defined by terms of linear Fibonacci-like sequences. By considering terms of such linear recurrences and additional free parameters, we define a nonlinear variant of these matrices via ratios of q-forms of terms of Fibonacci-like sequences whose indices are in nonlinear forms. We derive explicit formulae for the matrices L and U come from LU-decomposition, their inverses, inverse of the main matrices and their determinants.

A novel fluorescence sensor film for hydroquinone based on a graphene quantum dots-nano activated carbon composite

A novel film sensor, composed of graphene quantum dots-nano activated carbon, chitosan, and PVA, offers a simple and effective hydroquinone (HQ) detection. This film exhibits impressive HQ adsorption under ambient conditions (room temperature, pH 7, 3 h) and utilizes a readily observable fluorescence color change for quantification. Upon HQ binding, the film's fluorescence color shifts from yellow-green to blue, enabling a linear detection range of 1.0–150 mg⋅L−1 based on intensity analysis of the blue component (B value). Calibration curves generated on the same day (n = 3) exhibit high precision, with standard deviations of the linear equation parameters below 0.014 and a low detection limit of 0.5 mg⋅L−1. The film exhibits exceptional stability, retaining its color and performance for up to 20 days. This stability is further corroborated by recovery experiments utilizing HQ-spiked water samples at concentrations of 2.5 mg⋅L−1 and 40 mg⋅L−1, where recoveries of 106 % and 95 % were achieved, respectively. These results demonstrated the sensor's reliable quantification capabilities. Notably, the sensor exhibited insignificant interference from commonly co-existing substances such as ethanol, ascorbyl glucoside, arbutin, kojic acid, and methylene blue. However, Cu²⁺, Fe³⁺, and catechol did cause some interference. This versatility, coupled with its straightforward operation, makes the film sensor a promising candidate for on-site HQ detection in diverse environmental monitoring applications.

Synthesis of thermochromic CdHgI4 thin film: Insight into the thickness-dependent structural, morphological, linear, and nonlinear spectroscopic properties

This study introduces an in-depth exploration of structural, morphological, linear, and nonlinear optical properties of CdHgI4 thin films deposited by the thermal evaporation technique. In this study, cadmium tetra iodomercurate (CdHgI4) nanopowder was synthesized by fusion method from which thin films of various thicknesses (150 to 450 nm) were deposited on glass substrates by thermal evaporation technique. The Structural investigation conducted by X-ray diffractometer (XRD) established that both CdHgI4 nanopowder and thin film formed in a single phase with a tetragonal crystallographic system. However, the CdHgI4 nanopowder and films display a different preferred orientation as corroborated by texture coefficient determination (Tc). The microstructural features obtained by High-resolution transmission electron microscopy (HRTEM) revealed that the powder particles were agglomerated; however, the particles of thin film were well-defined with high compactness and uniform size. The purity as well as stoichiometry were judged by energy dispersive X-ray analysis confirming the absence of any impurities and samples adopted near stoichiometry features. The surface morphology done by field emission scanning electron microscope revealed that films constituted of nanostructured grains with noticeable growth particles with increasing thickness. The CdHgI4 nanopowder had a direct optical transition of band gap of about 1.41 eV evaluated from diffuse reflectance spectroscopy. The band gap of thin films determined from specular optical spectroscopy varied from 2.20 to 1.58 eV, as the thickness changed from 150 to 450 nm. The thickness dependence of other linear optical parameters, such as Urbach energy (Eu), refractive index (n), optical dielectric constants (ε1, ε2), the surface and volume energy loss (SELF, VELF), were elaborately discussed. The nonlinear optical properties including first-order linear susceptibility, third-order susceptibility (χ(1), χ(3)), NL refractive index (n2), and two-photon absorption coefficients (βc) were greatly dependent on the film thickness.

Quantifying nonlinear fracture parameters in bituminous SCB specimens: A compliance-based approach

Bituminous mixtures containing various defects, such as cracks and voids, exhibit ductile behavior in hot environments and brittle behavior in cold environments. Such materials can only be simulated realistically with the criteria of nonlinear fracture mechanics. In this investigation, the semi-circular bending (SCB) specimens, which have commonly been used to measure linear elastic fracture toughness parameters and fracture energy of asphalt and rock materials up to now, are studied to estimate several nonlinear fracture parameters of bituminous composites such as nonlinear fracture toughness, effective crack extension, critical crack tip opening displacement and brittleness. For this, the compliance functions of SCB specimens based on crack mouth opening displacement and load line displacement are derived by the finite element method at first. Subsequently, eight series of SCB tests in the literature, which were experimented with at low and room temperature environments, are examined by using two different compliance methods in fracture mechanics of quasi-brittle materials. This study's findings reveal that the crack extension in the pre-peak regime for mixes with bituminous at both low and normal temperatures is not statistically negligible and the use of nonlinear fracture toughness is, therefore, a necessity.

Structural and functional changes of the heart in patients with coronary heart disease who have had coronavirus disease COVID-19

The aim of the study: to investigate the effect of the previous COVID-19 coronavirus disease on the features of cardiac remodeling in patients with coronary heart disease (CHD). Materials and methods. 71 patients with CHD were involved in the study: stable angina pectoris II–III FC (age 69.0 (64.0; 76.0) years): 1 group (main) – 31 patients with CHD in long COVID-19 period; group 2 (comparison) – 40 patients with CHD without a history of COVID-19. Features of cardiac remodeling and energy work of the left ventricular (LV) myocardium were assessed using the echocardiography method. Results. CHD patients with a history of COVID-19 had greater changes in linear and volumetric parameters of the heart, an increase in the degree of hypertrophy of the LV myocardium, frequency of registration of LV diastolic dysfunction against the background of an increase in the mean pressure in the pulmonary artery, end-systolic pressure, decrease in global LV contractile function (LVF) compared to patients without COVID-19 history (p < 0.05). In CHD patients who suffered from COVID-19, there was an increase in the estimated energy expenditure of the LV myocardium: shock work by 14.77 % (U = 461.5; p < 0.05), potential energy by 34.68 % (U = 316.5; p < 0.05) and the pressure-volume zone by 17.78 % (U = 373.0; p < 0.05), which indicates a decrease in the speed of myocardial recovery in long COVID period. It was established that the presence of COVID-19 in the history of patients with CHD is associated with an increased risk of LV dilatation by 5.6 times (95 % CI 1.71–18.29; p < 0.05), LV myocardial hypertrophy by 3.05 times (95 % CI 1.79–5.91; p < 0.05), LV diastolic dysfunction by 1.44 times (95 % CI 0.91–2.29; p < 0.05), an increase in energy expenditure during heart work by 1.66 times (95 % CI 0.68–4.02; p < 0.05). Conclusions. Patients with coronary heart disease have more significant structural and functional changes and energy expenditure during the work of the heart, which proves the negative impact of SARS-CoV-2 on the state of cardiac remodeling in patients with CHD in long COVID-19 period.

Effect of metal chalcogenides on modifying the structural and optical properties of ZnWO4 nanostructure

Hydrothermal and thermolysis techniques were used to create ZnWO4 and 0.9ZnWO4-0.1MS (M = Cd, Zn, Pb) samples. The formed phases in each sample and their structure and microstructure were examined using Raman spectroscopy, Fourier-transform infrared spectroscopy and Rietveld refinement of Synchrotron x-ray diffraction data. The composition and morphology of the formed samples were investigated via scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS). The average crystallite size remains relatively constant regardless of the different metal chalcogenides. MS/ZnWO4 samples have two distinct morphologies. The UV diffuse reflectance spectroscopy (UV-DRS) technique is used to investigate the linear and nonlinear optical parameters for different samples. Alloying ZnWO4 with CdS or PbS affects the photo response region of the sample to include visible light. MS/ZnWO4 (MS=CdS, ZnS, PbS) samples have optical band gap values of 2.56, 2.43, 2.99 and 3.1 eV, respectively. The CdS/ZnWO4 and ZnS/ZnWO4 samples exhibit the highest refractive index and optical dielectric constant values within the visible range. CdS or PbS/ZnWO4 samples show the highest nonlinear optical parameters values within the visible range. The impact of MS samples on the photoluminescence emission of ZnWO4 was explored. The CIE chromaticity diagram reveals that MS/ZnWO4 (M = Zn and Pb) samples display a different degree of blue color while CdS/ZnWO4 sample reveals green-yellow colors.

Three-dimensional prediction of the nose for facial reconstruction: A preliminary study on North Indian adults

Forensic facial reconstruction is the last recourse to establish the identity of an unknown skull. The facial soft-tissue thickness (FSTT) is required to reconstruct various facial features on a skull. Unlike other facial features, the nose is made of cartilaginous tissue except for a small nasal bone. A large cavity (pyriform aperture) exists on the skull in place of the nose, which makes it a challenging job for reconstruction. The nose is a vital feature for the recognition of a face. Any change in the shape or size of the nose can alter the original aesthetic of the face. The present study proposes angles and regression functions on the bony structure to predict the various parts of the soft nose. A sample of computed tomography (CT) images of 100 males and 100 females aged between 18 and 45 years were included in the study. Apart from measuring fourteen linear parameters with three angles, simple linear regression models were derived for five pairs of parameters. Pearson's correlation coefficients for most of the parameters ranging between 0.221 and 0.872 were found to be significant at p ≤ 0.05 level. FSTT at three anatomical landmarks of the nose was also measured. A morphological observation study was undertaken to find the most frequent direction of the bony anterior nasal spine (ans) and its relation with the position of the pronasale (prn) on the soft nose. The devised parameters proposed in the study may also prove useful for reconstructing the nose in other populations.

Morphometric analysis of Mogamureru river basin at the YSR Kadapa District, Andhra Pradesh, India using GIS and remote sensing

Water availability and scarcity are impacted by geomorphological changes that occur within a catchment. As a result, determining the influence of geomorphological processes on the catchment’s hydrology requires a quantitative study of the catchment geometry. Approaches based on remote sensing (RS) and geographic information systems (GIS) have grown in popularity in recent years because they assist strategists and decision-makers in making accurate and effective choices and plans. For this research, the Mogamureru River basin was chosen. The study shows that GIS and RS data can be used to analyse and approximate the period and erosional operations’ risk in a Mogamureru river basin for better design and maintenance. The quickest and most economical method of displaying the hydrologic and physiographic features of the Mogamureru river basin is to assess the morphometric parameters. All of the following parameters such as: linear (7) areal (5), relief (5), and drainage texture (5) characteristics were obtained with hypsometric curve for the Mogamureru river basin utilizing the Shuttle Radar Topography Mission (SRTM) images. According to the linear parameter values, the majority of streams (82 %) belong to the first order, Statistical analysis shows that there is a good relationship between stream order and stream length, as well as stream order and stream number. The circularity ratio (0.55) depicts the young, elongated topography. The basin as a whole is in the mature stage of formation, with good to moderate potential, according to the hypsometric index (0.46). Due to land deterioration, Pulivendula and Vemula have had the most soil loss. This study concludes that morphometric analysis based on GIS & remote sensing techniques is a competent tool for hydrological studies. The research findings will help policymakers for integrated river basin management, agricultural development, and water management. In addition, researchers of morph hydrological, geological and climatological research will be beneficiary.

Quantitative study of the ossification centers of the body of sphenoid bone in the human fetus

The aim of the present study was to examine the growth dynamics of the two ossification centers of the body of sphenoid bone in the human fetus, based on their linear, planar and volumetric parameters. The examinations were carried out on 37 human fetuses of both sexes aged 18–30 weeks of gestation, which had been preserved in 10% neutral formalin solution. Using CT, digital image analysis software, 3D reconstruction and statistical methods, we evaluated the size of the presphenoid and postsphenoid ossification centers. The presphenoid ossification center grew proportionately in sagittal diameter, projection surface area and volume, and logarithmically in transverse diameter. The postsphenoid ossification center increased logarithmically in sagittal diameter, transverse diameter and projection surface area, while its volumetric growth followed proportionately. The numerical findings of the presphenoid and postsphenoid ossification centers may be considered age-specific reference values of potential relevance in monitoring the normal fetal growth and screening for congenital disorders in the fetus. The obtained results may contribute to a better understanding of the growing fetal skeleton, bringing new numerical information regarding its diagnosis and development.

An Improved Onboard Adaptive Aero-Engine Model Based on an Enhanced Neural Network and Linear Parameter Variance for Parameter Prediction

Achieving measurable and unmeasurable parameter prediction is the key process in model-based control, for which an accurate onboard model is the most important part. However, neither nonlinear models like component level models or LPV models, nor linear models like state–space models can fully meet the requirements. Hence, an original ENN-LPV linearization strategy is proposed to achieve the online modelling of the state–space model. A special network structure that has the same format as the state–space model’s calculation was applied to establish the state–space model. Importantly, the network’s modelling ability was improved through applying multiple activation functions in the single hidden layer and an experience pool that records data of past sampling instants, which strengthens the ability to capture the engine’s strongly nonlinear dynamics. Furthermore, an adaptive model, consisting of a component-level model with adaptive factors, a linear Kalman filter, a predictive model, an experience pool, and two ENN-LPV networks, was developed using the proposed linearization strategy as the core process to continuously update the Kalman filter and the predictive model. Simulations showed that the state space model built using the ENN-LPV linearization strategy had a better model identification ability in comparison with the model built using the OSELM-LPV linearization strategy, and the maximum output error between the ENN-LPV model and the simulated engine was 0.1774%. In addition, based on the ENN-LPV linearization strategy, the adaptive model was able to make accurate predictions of unmeasurable performance parameters such as thrust and high-pressure turbine inlet temperature, with a maximum prediction error within 0.5%. Thus, the effectiveness and the advantages of the proposed method are demonstrated.

Hyper-Rayleigh Scattering and Third-Harmonic Scattering in Chiral Liquids: Basic Evidences and Differences with Linear Chiroptical Techniques.

Nonlinear chiroptical methods like hyper-Rayleigh optical activity (HROA) and third-harmonic optical activity (THOA) have a great potential in characterizing structure-chiroptical properties of molecular systems. Here, with these methods, we bring for the first time experimental and theoretical evidence of nonlinear chiroptical differences between enantiomers of simple chiral molecules, using exclusively linearly polarized incident light. The origin of these unexpected nonlinear chiroptical contributions comes from a new nonlinear source term of the form βOA(∇×μ(nω)), which is a bilinear coupling term including the linear chirality parameter, βOA, and the curl of the nonlinear induced electric dipole moment, μ(nω), both involving dipolar magnetic interactions. Through a simple nonlinear chiroptical model that we propose, we show that specific nonlinear chiroptical parameters can be quantified, thus bringing new insights into stereochemical and electronic structural features of molecular and supramolecular systems.

Структурные особенности коренных сосняков северной и средней тайги при пирогенных воздействиях

The study of indigenous pine forests of evolutionary formation as endangered virgin forests is the basic for fundamental research into the processes of formation of sustainable forest communities. The aim of the study presented in the article is a comparative assessment of the structures of tree fractions of phytocenoses according to the parameters of the age series of stands and the successional position, dynamic indicators of woody waste, the influence of the pyrogenic factor, and the presence of rot damage to the stands. Age structures, numerical and linear parameters of pyrogenic factors, their impact on the infestation of trees with rot, volumetric indicators of wood waste and characteristics of natural regeneration, the mass of wood xylolysis products during its decomposition by wood-destroying fungi have been studied in pine biogeocenoses with various dynamic characteristics in the taiga zone of European Russia. Pine biogeocenoses under these conditions have structures of different ages, altered by fires of different types. Using the example of an indigenous pine forest in the Pechora-Ilychskiy Nature Reserve (middle taiga), the influence of pyrogenic effects on the formation of various types of rot and damage to trunks is shown. The volumes of woody waste are distributed according to the stages of decomposition in pine forests with different structural and dynamic characteristics; pine undergrowth – according to height gradations. An example is given of calculating the mass of wood components deposited in the stands and released during the decomposition of woody waste by wood-destroying fungi for the biogeocenosis of the Pechora-Ilychskiy Nature Reserve. The majority of indigenous pine forests in the northern territories have been affected by fires of varying intensity and types, sometimes several times during a development cycle. Pyrogenic effects have a significant on changes in the age structures of pine forests, damage to their trunks, the general infestation of forest stands by wood-destroying fungi of the biotrophic complex, the volumes of woody waste, and the formation of natural regeneration structures.

Comparative Performance of Non-Stationary Intensity-Duration-Frequency (NS-IDF) Models for Selected Gauge Stations in the Niger Delta

This study focused on a comparative analysis of developed Non-stationary rainfall intensity-duration-frequency (NS-IDF) models with existing IDF models for the Niger Delta with Uyo, Benin, Port Harcourt, and Warri as selected stations. Applied was 24-hourly (daily) annual maximum series (AMS) data with downscaling models also used to downscale the time series data. Uyo and Benin had statistically significant trends with Port Harcourt and Warri showing mild trends. The best linear behavioural parameter extremes model integrating time as co-variate was selected for each station for computation of the General extreme value (GEV) distribution fitted NS-IDF models with the open-access R-studio software. The Non-stationary intensity values were higher than computed stationary ones, with significant differences at a 5% significance level for a given return period. For example, for 2 and 10-year return periods for 1-hour storms the differences of 22.71% & 17.0%, 15.24% & 9.40%, 5.09% & 4.04%, and 6.15% & 4.43% for Uyo, Benin, Port Harcourt and Warri, respectively were recorded. While, the percentage difference in intensities was very high between the Non-stationary and existing, Stationary IDF models. For a return period of 2 years at 15 and 60 min durations, the differences were 97.9 & 3.2%, 240.6 & 67.2%, 78.2 & 0%, and 121.6 & 50.1% for Uyo, Benin, Port Harcourt and Warri, respectively. Such extreme value difference in intensity underestimates the peak flood and exagerate the flood risk. The general NS-IDF calibrated models showed very good match and fit with R<sup>2</sup> = 0.977, 0.999, 0.999 & 0.999, and MSE accuracy = 193.5, 1.011, 4.1552 & 1.011 for Uyo, Benin, Port Harcourt, and Warri, respectively. Erosion and flood control facilities in the Niger Delta require upgrading using the calibrated general NS-IDF models to accommodate extra-value rainfall intensities due to climate change.

Relation between orthodontic malocculusion and maxillary sinus volume.

This study aimed to determine maxillary sinus volume (MSV) in different skeletal malocclusion classes and the correlation between MSV and craniofacial morphology on Cone Beam Computed Tomography (CBCT). The study was performed retrospectively on CBCT images of individuals aged 12-24 years. A total of 129 patients (70 females, 59 males) with a normal vertical growth pattern (27° ≤ SNGoMe ≤ 38°) were divided into three groups according to malocclusion. Group 1 consisted of Class I (1 ≤ ANB ≤ 4) (n = 46) patients, Group 2 consisted of Class II (ANB > 4) (n = 47) patients, and Group 3 consisted of Class III (ANB < 1) (n = 36) patients. Four angular (SNA, SNB, ANB, SNGoMe) and linear (S-N, ANS-PNS, S-Ar, N-ANS) parameters were measured to evaluate craniofacial morphology. Right and left MSV were measured using Dolphin 11.0 (Dolphin Imaging, Chatsworth, CA, USA) Imaging software. Pearson's correlation analysis was performed to assess statistical correlation. MSV was larger in males than females (male AMSV = 14244.1 ± 4735.8, female AMSV = 12778.2 ± 4606.9 p = 0.011) in the general population, but just the Class II group showed this (male AMSV = 16089.6 ± 4330.4, female AMSV= 12705.9 ± 3210.2, p = 0.008). RMSV and LMSV were similar (female p = 0.181 male p = 0.097), and MSV showed no significant differences between the different malocclusion classes in both sex (female p = 0.315, male p = 0.118). In the Class III group, SNB was positively correlated with RMSV (r = 416, p = 0.012). MSV showed significant positive correlation with N-ANS in all groups (Class I r = 0.359, p = 0.014, Class II r = 0.336, p = 0.021, Cl III r = 0.387, p = 0.02). In the Class II and Cl III groups, there is a statistically significant correlation between MSV and the S-N parameter (Class II r = 0.304, p = 0.038, Class III r = 0.412, p = 0.013). ANS-PNS parameter was measured at the lowest statistically significant level (female 43.1 ± 3.9a, p < 0.001, male 43.1 ± 4.3a, p < 0.001) in the Class III group but no correlation was found with MSV. Only Class II group showed a weak positive correlation between MSV and ANS-PNS (r = 0.314, p = 0.032). There was no difference regarding MSV between malocclusion classes. Class II males exhibit significantly larger MSV compared to females. There is a correlation between MSV and SNB, S-N, N-ANS and ANS-PNS parameters for various orthodontic skeletal patterns. Further studies are needed to understand the relationship between MSV and different skeletal structures.

Acute Effects of Caffeine and Taurine on Linear and Nonlinear Measures of the Cardiovascular System in Young Adults

The use of beverages containing caffeine has increased significantly in recent years due to their stimulant effects. The aim of this study was to determine the possible adverse effects of caffeine and taurine on young adults’ cardiovascular systems using linear and nonlinear parameters for this analysis. This study was carried out with 56 students from Aydın Adnan Menderes University. The participants were divided into four main groups: caffeine, taurine, caffeine + taurine, and a control. Blood pressure and electrocardiogram measurements were performed before the ingredients were consumed. After 30 and 60 min, the measurements were repeated. Linear and nonlinear analyses were performed on the heart rate variability data 60 min after consumption. Compared with taurine and the combination of caffeine + taurine, caffeine was found to have the most adverse effects on the hemodynamic parameters and the linear and nonlinear parameters of heart rate variability in the young adult participants. It was also found that the presence of taurine may have repressed the adverse effects of caffeine.

Parameter learning for Wiener systems with time‐delay state‐space model

AbstractThis paper discusses a novel scheme for learning the Wiener output error nonlinear system with time‐delay state‐space model. In the Wiener system, the dynamic linear block is approximated by time‐delay state‐space model, and the static nonlinear block is established using neural fuzzy network. Combined signals designed including separable signal and random signal are devoted to achieving parameters separation learning of the Wiener system, that is, the two blocks are learned independently. Firstly, using the properties of shift operator and transforming state‐space model with time‐delay into a representation with input and output, then linear dynamic block parameters are learned by the virtue of correlation analysis method in the condition of Gaussian signals. Moreover, a recursive extended least squares estimation is carried out to learn parameters of static nonlinear block and colored noise model under the condition of random signals. The efficiency and accuracy of proposed scheme are confirmed on experiment results of a numerical simulation and a typical practical nonlinear process, and experimental simulation results demonstrate that the learning scheme proposed obtains good learning precision.

Reliability of glenoid measurements performed using Multiplanar Reconstruction (MPR) of Magnetic Resonance (MRI) in patients with shoulder instability

PurposeMeasurement of glenoid bone loss in the shoulder instability can be assessed by CT or MRI multiplanar imaging and is crucial for pre-operative planning. The aim of this study is to determine the intra and interobserver reliability of glenoid deficiency measurement using MRI multiplanar reconstruction with 2D assessment in the sagittal plane (MPR MRI).MethodsWe reviewed MRI images of 80 patients with anterior shoulder instability with Osirix software using MPR. Six observers with basic experience measured the glenoid, erosion edge length, and bone loss twice, with at least one-week interval between measurements. We calculated reliability and repeatability using the intra-class correlation coefficient (ICC) and minimal detectable change with 95% confidence (MDC95%).ResultsIntra and Inter-observer ICC and MDC95% for glenoid width and height were excellent (ICC 0,89-0,96). For erosion edge length and area of the glenoid were acceptable/good (ICC 0,61-0,89). Bone loss and Pico Index were associated with acceptable/good ICC (0,63 -0,86)) but poor MDC95% (45 - 84 %). Intra-observer reliability improved with time, while inter-observer remained unchanged.ConclusionThe MPR MRI measurement of the anterior glenoid lesion is very good tool for linear parameters. This method is not valid for Pico index measurement, as the area of bone loss is variable. The pace of learning is individual, therefore complex calculations based on MPR MRI are not resistant to low experience as opposed to true 3D CT

Modification in the Optical and Dielectric Characteristics of Poly (Vinyl Alcohol)/Carboxymethyl Cellulose Blended Polymers Doped with Two Phases Nanocomposites for Application in Optoelectronic and Energy Storage Devices

Nanocomposite films comprised of poly (vinyl alcohol) (PVA) and carboxymethylcellulose (CMC) were fabricated via a solution casting procedure, with the incorporation of (1-x)CuCo2O4/xZnMn2O4. Our research described here was aimed to explore the impact of the (1-x)CuCo2O4/xZnMn2O4 on the structural, optical and electrical features of the PVA/CMC blended polymer, using various techniques. The different phases formed (CuCo2 O4 and/or ZnMn2O4) in (1-x) CuCo2O4/x ZnMn2O4 filler samples were identified applying Rietveld refinement analysis. The structures and morphologies of the PVA/CMC/(1-x)CuCo2O4/xZnMn2O4 blend composites were determined using X-ray diffraction and scanning electron microscopy techniques. Their various linear and nonlinear optical parameters were examined using the diffused reflectance technique. The blended polymer composite with x = 0.1 displayed the highest absorbance. The transmittance of the PVA/CMC blend declined from 91 to 69% when it was loaded with a nanocomposite containing 10% ZnMn2O4. The optical band gaps of the doped blend composites had their lowest values, 5.45 eV for direct transition and (4.83, 2.99, 2.31) eV for the indirect transition, as the blend was loaded with the fillers containing 10 and 15% ZnMn2O4. The study also explored the influence of the (1-x)CuCo2O4/x ZnMn2O4 on the fluorescence spectra and chromaticity diagram of the PVA/CMC blend. The effect of the filler on the complex dielectric constant, complex electric modulus, ac conductivity and electrical storage energy of the host blend was examined. The obtained characteristics imply potential utility of the doped blends in photocatalytic, UV-blocking, UV-filtering, optoelectronic, electrical storage, nonlinear optical and photonic applications.

A novel approach for state-of-charge estimation of lithium-ion batteries by quasi-static component generation of ultrasonic waves

Lithium-ion batteries content complex internal components, such as porous media and electrolytes, which result in strong scattering and high attenuation of ultrasonic waves in these batteries. The low attenuative feature of the quasi-static components (QSCs) of ultrasonic waves offers great potential for nondestructive assessment of highly attenuating and porous materials. This paper presents an innovative approach for estimating the state-of-charge (SOC) of lithium-ion batteries using QSC of ultrasonic waves. Experimental results demonstrate a clear and repeatable linear relationship between the amplitudes of the generated QSC and the SOC of lithium-ion batteries. In addition, the relationships between different SOCs of the battery and the conventional linear ultrasonic parameters, second harmonic generation (SHG), and the QSC were compared to verify the improved sensitivity of the proposed approach. Notably, compared to linear ultrasonic features and the SHG, the generated QSC shows much higher sensitivity to the variations of SOC. We employ the phase-reversal method to further enhance the signal-to-noise ratio of measured QSC signals. The experimental results demonstrate that the proposed method exhibits a heightened sensitivity to changes in the SOC of batteries, resulting in significantly enhanced detection accuracy and resolution. This method effectively addresses the deficiencies observed in the current detection methods such as limited accuracy and sluggish response times. This method provides a new solution to overcome this challenge. Meanwhile, it also confirms that nonlinear ultrasound promises an alternative method for SOC assessment, providing a foundation for efficient and safe battery management practices.

Macroscopic trends of linear tearing stability in cylindrical current profiles

The likelihood of realising tokamak power-plants will be greatly improved by the discovery of high-gain equilibria that resist the formation of small islands and hence avoid the disruptive neoclassical tearing mode. We propose a series of studies to understand how simple tokamak design can leverage aspects of tearing onset physics to maximise passive resistance to island formation. Here we investigate the variation that current profiles can bring about in preventing tearing onset through the cylindrical linear tearing stability parameter Δ′ . A database of 159148 realistic pilot-plant current profiles was generated with Monte Carlo sampling, and the distribution of Δ′ values was linked with interpretable profile characteristics. In agreement with prior theoretical and experimental studies, Δ′ was found to be strongly correlated with the existence and steepness of a local toroidal current well or hill, with the former destabilising and the latter stabilising. In the absence of these two cases, the remaining Δ′ values were linearly bounded by the toroidal current gradient at the rational surface.