Notch Depth Research Articles

A cephalometric analysis of the antegonial notch in relation to the direction of mandibular growth.

Masticatory muscle forces influence craniofacial morphology development. The antegonial notch (Notch) is a bony concavity on the inferior border of the mandible. Considering the Notch is located anteriorly to the insertion of the masseter muscle and varies among individuals, we hypothesised that these muscles influence the formation of the Notch. Therefore, this study aimed to investigate the correlation between mandible morphology and Notch formation. Sixty Japanese patients who visited the Department of Orthodontics at our university hospital were retrospectively evaluated. Morphological and morphometric analyses of the Notch and related craniofacial parameters were conducted using lateral cephalograms taken at the patients' initial visits. Standard values for the Notch area and depth were determined, and the morphology of the Notch and mandible was analysed using Spearman's rank correlation coefficient (p < 0.05). The mean Notch area and depth was 78.71 ± 36.54 mm2 and 3.11 ± 1.09mm, respectively. The Notch area was significantly correlated with ramus inclination (p = 0.044, r = 0.261) and with the Y-axis (p = 0.039, r = 0.267). This study indicated that both the masticatory muscles and mandibular growth could contribute to the Notch formation.

Mandibular morphology in schizophrenia patients compared with non-psychiatric controls using digital panoramic radiography: a retrospective cross-sectional study from Istanbul, Türkiye

BackgroundSchizophrenia is a chronic severe mental disorder characterized by impairment in cognition, emotion, perception, and other aspects of behavior. In light of the association of craniofacial dysmorphology with schizophrenia, mandibular morphology may provide clues about the role of neurodevelopment in the pathophysiology of schizophrenia. This retrospective cross-sectional study aimed to compare the mandibular morphology of patients with schizophrenia with controls using digital panoramic radiography (DPR).Methods302 recorded diagnostic panoramic images obtained from 143 schizophrenia patients (98 males, 45 females), and 159 controls (73 males, 86 females), aged 18–45 years, were evaluated. Seven mandibular measurements consisting of ramus height, condylar height, gonial angle, antegonial angle, antegonial notch depth, ramal notch depth and bigonial width were measured from the DPRs in a double-blinded manner. Bivariate comparisons were carried out using the Independent t-test and Mann–Whitney U test. Logistic regression analysis was used for multivariate comparisons.ResultsLinear measurements were higher while angular measurements were lower in schizophrenia patients. Regression analyses indicated that female patients had greater ramus height (OR = 1.243; P = 0.001), condylar height (OR = 1.463; P = 0.048) and bigonial width (OR = 1.082; P < 0.001); male patients had greater ramus heights (OR = 1.216; P = 0.001) and bigonial width (OR = 1.076; P < 0.001) as well as lower antegonial angle (OR = 0.908; P = 0.012) compared to their respective controls.ConclusionQuantitative differences in mandibular morphology in schizophrenia patients versus controls deserve attention and corroborate with the concept of abnormal neurodevelopment in schizophrenia.

Determination of Mandibular Morphology in a Turkish Population With Bipolar I Disorder Using Panoramic Radiography.

The presence of specific craniofacial deviations may be evidence of abnormal early brain development in bipolar disorder (BD). This study aimed to compare mandibular morphology in patients with BD versus nonpsychiatric controls using panoramic radiography. A total of 215 recorded images, 70 patients with BD and 145 controls, were evaluated. Seven mandibular parameters of the ramus height (RH), condylar height (CH), gonial angle (GA), antegonial angle (AGA), antegonial notch depth (AND), ramal notch depth (RND), and bigonial width (BGW) were measured in a blinded manner. Group analysis was conducted separately for males and females. The univariate comparisons showed increased values in RH, CH, AND, RND, and BGW and decreased values in GA in males with BD compared with male controls. In addition, females with BD had higher RH, CH, RND, and BGW values in comparison to female controls. The differences were statistically significant. Data from multivariate analyses revealed that increases in RH and BGW values in both sexes were significant predictive variables that distinguished patients with BD from controls. Moreover, deeper AND was the most prominent predictor that distinguished male patients with BD from male controls. The identification of subtle changes in mandibular measurements is consistent with the notion of impaired neurodevelopment in BD.

The morphometry of distal tibia and posterior malleolus and its clinical implications in total ankle prosthesis.

The aim of this study is to reveal the morphometry of the distal tibia and posterior malleolus and to generate morphometric reference data for the tibial component of total ankle prosthesis. This study was performed on 121 human dry tibiae (47 right, 74 left). The morphometric measurements of distal tibial structures, tibial length and the distance between the medial and posterior malleolus were measured in this study. Measurements on 44 tibiae were repeated three times and averaged for minimizing intra-observer error. The tibial length was found 34.19 ± 2.31cm. Mean values of width of fibular notch at tibial plafond and 10mm proximal to the tibial plafond were 25.71 ± 2.44mm and 17.81 ± 2.46mm, respectively. Mean depth of fibular notch at tibial plafond and 10mm proximal to the tibial plafond were 3.60 ± 1.04mm and 3.37 ± 1.24mm, respectively. Mean height of fibular notch was found 48.21 ± 10.51mm. Mean width and height of medial malleolus were 25.08 ± 2.13mm and 14.73 ± 1.85mm, respectively. Mean width and length of tibial plafond were 27.71 ± 2.74mm and 26.96 ± 2.62mm, respectively. Mean values of width and height of posterior malleolus were measured 21.41 ± 3.26mm and 6.74 ± 1.56mm, respectively. Mean distance between medial and posterior malleolus was found 37.17 ± 3.53mm. Mean width and depth of malleolar groove were 10.26 ± 1.84mm and 1.73 ± 0.75mm, respectively. The mean intra-class correlation values were found between the 0.959 and 0.999. Knowing the distal tibial morphometry is crucial for designing convenient ankle replacement implants for Turkish population. To our knowledge, this study is the first in the literature that identifies posterior malleolar morphometry on dry tibiae. We believe that this study will make a significant contribution to the literature about distal tibial morphometry and especially the posterior malleolus and the data of our study can be used for designing total ankle prosthesis in Turkish population.

Performance degradation evaluation of square steel tubes with local penetration damage

Steel tubular structures are susceptible to welding defects, cracking defects and environmental corrosion, which can negatively affect the stability and reliability of structure. This study tested the axial compression performance of twenty-six square steel tubular stubs with localized penetration damage simulated by artificial notch, considering the influence of notch length, orientation, and position. The test results showed that the failure mode of the specimens was dominated by the local buckling along the direction of the notch axis. The failure mode of the specimen with vertical notch showed notch opening, while those with horizontal notch showed notch closing, resulting in the secondary peak value in the load-displacement curve. The existence of local penetration damage reduced the ultimate strength and ductility of the tubular stubs. Compared to the ultimate strength of the specimens with middle notch, those with corner notch were weakened more, up to 27 %. Furthermore, the effects of notch dimension, position, orientation, and tube wall thickness on the axial bearing capacity of square steel tubular stubs are discussed by using a validated finite element model. Owing to the analysis, the ultimate strength of the stubs is reduced by increasing notch length, width and depth, whereas the reduction effect tends to be weakened as the notch orientation angle increases. The notch located in the corner is the most unfavorable for the axial compression performance of the square steel tubular stubs. A semi-empirical formula for evaluating the ultimate strength of square steel tubular stubs with local penetration damage is proposed by introducing the strength reduction factor. An artificial neural network-based ultimate strength prediction model is developed that can consider the effects of wide-range parameters, achieving high accuracy.

Morphologic predictors of mandibular changes induced by Sander's Bite Jumping Appliance.

This study aimed to identify pretreatment cephalometric variables as possible predictors of the mandibular length increase in Class II patients with mandibular retrusion, treated by means of the Bite Jumping Appliance (BJA). Forty-three subjects (22 males and 21 females) with Class II malocclusion, treated with a BJA, were selected on the basis of the following inclusion criteria: full Class II molar relationship, Overjet (OVJ) ≥ 6 mm and a skeletal Class II malocclusion with mandibular retrusion at the start of the treatment (T0); cervical vertebral maturation stage 2 or 3 at time 0 (T0). The following mandibular structural features were measured on lateral cephalograms at time 0 and time 1 (15 months of treatment): the width and height of the mandibular symphysis and its width/height ratio, the width and height of the mandibular ramus and its width/height ratio, the antegonial notch depth and the Condilion-Gonion-Menton (Co-Go-Me) angle. Post-treatment changes were assessed by Pancherz's cephalometric analysis, evaluating the increases in mandibular length. A regression statistical model was used to test the association between morphologic variables and mandibular length changes. At T1, a significant increase in mandibular length (7.1 + 3.4 mm, p < .001) was measured. A significant negative association between the pretreatment Co-Go-Me angle and mandibular length change was found (p < .05). IMPA angle was negatively associated with mandibular length change. All the others morphological feature were not statistically related to mandibular length change. Co-Go-Me angle and IMPA angle at T0 can be used as predictors for mandibular response to the treatment with BJA.

Pre-stress effect of metal bars in low-stress separation technology

This paper proposes a low-stress separation technology based on pre-stress effect. It connects notching and loading to take advantage of the rotating bending fatigue to achieve the cropping of metal bars. The real-time positions of the notching tool and loading hammer are calculated based on energy equivalence theory. Compared to the conventional notching method, it achieves 25.1 % reduction of cutting force in the case of AISI1045 steel bars. A testing platform is set up and the loading curve is designed to meet the requirements of deflection law and fatigue cyclic loading law. The bending stress for the minimum cutting force, crack angle and deviation under different notch parameters, and the reasonable pre-loading of different materials are determined through cropping tests and finite element simulation. Cropping results indicate that the optimized notch angle and depth are 60° and 1.5 mm, respectively.

Development of a cyclic semi-circular bending test protocol to characterize fatigue cracking of asphalt mixture at intermediate temperature

The Semi-Circular Bending (SCB) test has been traditionally conducted in a monotonic loading and displacement-controlled mode at intermediate temperature to assess the fatigue crack resistance of asphalt mixtures. However, fatigue damage is essentially deterioration in material integrity as a result of repeated loading. The SCB monotonic loading does not realistically reflect the traffic loading repetition. This may have limitation on mechanism of the fatigue cracking in asphalt mixture. This study aims to develop a cyclic SCB test protocol to characterize the fatigue cracking of asphalt mixtures. Digital Image Correlation (DIC) was utilized to identify crack length associated with the number of loading cycles applied. A full factorial design was conducted for the optimization of testing parameters of the cyclic SCB test, including three levels of notch depth and loading frequency. Two indicators including the number of cycles to failure and Paris’ Law coefficients were used to characterize the fatigue cracking resistance of asphalt mixture. The proposed test protocol of cyclic SCB was validated by three asphalt mixtures of good, medium, and poor cracking performance. The critical strain energy release rate Jc of three mixtures is also measured by the monotonic SCB test for studying the relationship between Jc and Paris’ Law coefficients. The results indicate that Paris’ Law coefficients have relatively low variance compared to the number of cycles to failure and are independent of notch depth and loading frequency. The optimal testing parameter combination of 25 mm notch depth and 10 Hz loading frequency was recommended in perspective of test variance and test practicability. The Paris Law coefficient n ranking was consistent with the one of fatigue cracking resistance of asphalt mixtures evaluated.

New quantitative analyses of the Nacholapithecus kerioi proximal ulna confirm morphological affinities with Equatorius and large papionins.

The elbow of Nacholapithecus has been extensively described qualitatively, however its ulnar morphology has never been the focus of an in-depth quantitative analysis before. Hence, our main aim is quantifying the proximal ulnar morphology in Nacholapithecus and exploring whether it is similar to those of Equatorius and Griphopithecus as previously reported. We compared Nacholapithecus proximal ulnar morphology with a sample of extant and extinct anthropoids through principal component analysis and agglomerative hierarchical cluster analysis. Moreover, we calculated the Cophenetic Correlation Coefficient and checked for taxonomical group mean differences through MANOVA and pairwise post-hoc comparisons, as well as the phylogenetic signal in the variables used. The Nacholapithecus ulna displays a moderately long and relatively narrow olecranon, a relatively wide trochlear surface-radial notch width, and a relatively thin sigmoid notch depth. These features resemble those of large papionins and chimpanzees, and some extinct taxa, mainly Equatorius. Results presented here reinforce previous inferences on the functional morphology of the Nacholapithecus elbow, showing adaptations for general quadrupedal behaviors. However, other derived features (e.g., a relatively wide trochlear surface) might be associated with the ape-like traits described for its distal humerus (e.g., wide trochlear groove), thus displaying a combination of primitive and derived features in the proximal ulna. Finally, affinities with large papionins could suggest the presence of some terrestrial habits in Nacholapithecus. However, the lack of evidence in the rest of the skeleton prevents us from suggesting terrestrial affinities in this taxon in a conclusive manner.

Pipeline Circumferential Cracking in Near-Neutral pH Environment Under the Influence of Residual Stress: Dormancy and Crack Initiation

The purpose of this study is to identify the integrity challenges encountered by buried pipeline steels, specifically to address Circumferential Near-Neutral pH Corrosion Fatigue (C-NNpH-CF). Damage to the pipeline’s protective coating and corrosion conditions increase the risk of service failures caused by C-NNpH-CF. (Note that this mechanism has previously been termed near-neutral pH stress corrosion cracking.) Unlike axial cracking, circumferential cracking is primarily influenced by residual stress from pipeline bending, geohazards, and girth welds. External corrosion pits often lead to dormant cracks, with growth ceasing around 1 mm depth due to reduced dissolution rates. Investigating the impact of bending residual stress (an appropriate source of axial residual stress) and cyclic loading (simulated pipeline pressure fluctuation), the study employs the digital image correlation (DIC) method for stress distribution analysis. Factors like applied loading, initial notch depth, and bending conditions influence crack initiation and recovery from the dormancy stage by affecting stress distribution, stress cells, and stress concentration. Cross-sectional and fractographic images reveal time/stress-dependent mechanisms governing crack initiation, including dissolution rate and hydrogen-enhanced corrosion fatigue. The study emphasizes the role of various residual stress types and their interactions with axial cyclic loading in determining the threshold conditions for crack initiation.

Numerical study of cooling performance and flow characteristics of film hole-broken rib composite structure with squealer tip

The gas turbine blade tip might face substantial heat loads because of leakage flow between the blades and the casing. For blade tip cooling, a composite cooling structure with film holes and broken ribs is first used on GE-E3 blade in this work. The flow and cooling characteristics of the innovative structure are studied by numerical simulation under various blowing ratio (BR) conditions. Meanwhile, the impact of modifying both the rib angle and the rib height on the adiabatic film cooling effectiveness (AFCE) at the tip of the squealer is analyzed. According to the results, adding rib structures to the squealer tip can effectively regulate the paths of cavity vortices and kidney-shaped vortex pairs (KVP) at the tip. As a result, the averaged AFCE at the blade tip is improved. The notch pressure-side broken rib structure has good aerothermal performance, and the highest AFCE at BRs of 0.50, 1.00, and 1.50 basically occur under the “R60-100 %” condition (R60 refers to the rib structure of 60°, and 100 % is the ratio of rib height to notch depth), and the corresponding AFCE are 27.71 %, 26.00 %, and 32.47 % higher than those of the no-rib case, respectively. The corresponding AFCE increased by 27.71 %, 26.52 %, and 32.47 %, respectively, compared to the no-rib condition. The highest AFCE at a BR of 1.50 occurs at “R75-70 %“, which is a 38.20 % increase in AFCE compared to the no rib case. The improvement in AFCE is due to the difference in the flow of the cooling jets, which are subject to cavity vortices at different BRs. The analysis shows that the addition of ribs disrupts the formation of KVPs and weakens the influence of the cavity vortex, thus reducing the low AFCE region at the lower end of the tip groove and increasing the AFCE. However, due to the blocking effect of the ribs, the pressure loss at the blade tip is elevated. The proposed blade tip cooling structure is expected to provide new ideas for the next generation of advanced gas turbine cooling designs.

Design and Analysis of a High-Gain, Low-Noise, and Low-Power Analog Front End for Electrocardiogram Acquisition in 45 nm Technology Using gm/ID Method

In this work, an analog front-end (AFE) circuit for an electrocardiogram (ECG) detection system has been designed, implemented, and investigated in an industry-standard Cadence simulation framework using an advanced technology node of 45 nm. The AFE consists of an instrumentation amplifier, a Butterworth band-pass filter (with fifth-order low-pass and second-order high-pass sections), and a second-order notch filter—all are based on two-stage, Miller-compensated operational transconductance amplifiers (OTA). The OTAs have been designed employing the gm/ID methodology. Both the pre-layout and post-layout simulation are carried out. The layout consumes an area of 0.00628 mm2 without the resistors and capacitors. Analysis of various simulation results are carried out for the proposed AFE. The circuit demonstrates a post-layout bandwidth of 239 Hz, with a variable gain between 44 and 58 dB, a notch depth of −56.4 dB at 50.1 Hz, a total harmonic distortion (THD) of −59.65 dB (less than 1%), an input-referred noise spectral density of &lt;34 μVrms/Hz at the pass-band, a dynamic range of 52.71 dB, and a total power consumption of 10.88 μW with a supply of ±0.6 V. Hence, the AFE exhibits the promise of high-quality signal acquisition capability required for portable ECG detection systems in modern healthcare.

Fatigue of notched steel hollow sections under sinusoidal cyclic loading

Abstract This paper presents the numerical modelling of the fatigue of notched steel hollow sections under sinusoidal cyclic loading. Steel hollow sections are commonly used as structural components, particularly for beams, columns, girders, trusses and bracing. The biggest concern is flaws or minor cuts that create notches in the steel hollow sections. The presence of a notch could degrade the strength properties and consequently lead to severe disadvantages in fatigue life. The fatigue assessment was carried out using the finite element program WELSIM. SHS50×50×3.0 was selected for the three-dimensional model. The sinusoidal cyclic loading was applied with a minimum force of 1.665 kN and a maximum force ranging from 5.550 kN to 16.65 kN. Variables such as notch depth and amplitude ratio were simulated to acquire the stress range and the number of cycles. The results showed that the stress range for unnotched specimens is 46.258 MPa to 164.93 MPa; for notched specimens, it is 52.273 MPa to 189.89 MPa. It was found that the presence of a notch leads to an increase in the stress range and a decrease in the number of cycles. The unnotched specimens can withstand the number of cycles from 1.83×106 to infinity. Meanwhile, the number of cycles for notched specimens ranges from 1.20×106 to 8.36×107. At each amplitude ratio, except for A = 0.10, the number of cycles is insignificant.

Numerical simulation of axially loaded circular concrete-filled steel tubular short columns with localized corrosion

Concrete-filled steel tubular (CFST) columns are widely utilized in structures owing to their cost-effectiveness, high strength, ductility, and proven fire resistance. Despite these advantages, concerns persist regarding the performance of CFST columns with locally corroded steel tubes, impeding their widespread adoption in offshore structures. This research employs three-dimensional finite element (FE) simulations for circular CFST stub columns subjected to axial compression, validated against experimental data. Verification includes full load-displacement histories, ultimate axial strengths, and failure modes. The validated FE models are then employed to assess and compare the structural behavior of CFST columns with various shapes of localized corrosion, analyzing overall load-deformation curves, interaction stress-deformation responses, and composite actions. To acquire critical data for understanding stub column behavior, 81 specimens underwent non-linear finite element analysis, with local corrosion represented by artificial notches in steel tubes. Test parameters, such as notch orientations, lengths, depths, widths, and concrete compressive strength, are varied. Results elucidate the impacts of these parameters on different aspects of stub column responses with corroded steel tubes. Furthermore, the accuracy of existing design models in predicting the ultimate axial strengths of CFST columns with corroded steel tubes is assessed. Finally, through parametric analysis of test results, a practical model is proposed and verified for computing the peak resistance of a CFST stub column with a locally corroded steel tube.

New approach to low-cycle fatigue lifetime prediction for deep-rectangular notched components with finite residual thickness: Experiment and simulation

The introduction of notches in engineering components often has detrimental effects on fatigue behavior. Current research on finite residual thickness is extremely limited, especially when dealing with more complex geometric shapes of notches. In this study, the low-cycle fatigue (LCF) life of cylindrical components with deep-rectangular notches were predicted based on the theory of critical distance (TCD) and the total stress field (TSF) method. The results indicated that the presence of stress concentration near the notch accelerated the initiation and propagation of cracks. Furthermore, finite element method (FEM) was conducted, revealing the need to comprehensively consider the stress distribution across the residual thickness zone (RTZ) for notched specimens. Through numerical method improvement and geometric modeling optimizations, the accuracy of fatigue lifetime prediction has been refined to within a margin of ± 1.5. Comparative simulations on notched specimens with various ratio of notch depth to residual thickness were conducted, characterizing the fatigue process zone (FPZ) near the notch root under LCF loading for Q345R steel, indicating that characteristic material parameter d* exhibits minimal fluctuations with changes in the notch size, while the corresponding local stress levels display a logarithmic upward trend, substantiating that fatigue lifetime decreases with larger notch sizes.

PMCT-based sex determination using posterior segment of greater sciatic notch in North Indian population

BackgroundDigital tools, which offer superior accuracy compared to manual metrics, utilize radiological images for noninvasive data collection, providing a convenient means of obtaining skeletal data. The greater sciatic notch exhibits high sexual dimorphism and resistance to damage, and therefore serves as a viable tool for sex determination in poorly preserved skeletons, particularly in scenarios involving mass disasters, highly putrefied, and skeletonized cases. In addition to the width and depth of the greater sciatic notch, the length and angle of the posterior segment are highly specific parameters. This study aims to obtain accurate and standardized values for determining sex by measuring the posterior segment of the greater sciatic notch using postmortem computed tomography with a 16-slice multidetector row computed tomography scanner.ResultsThe study revealed that except for depth and the distance between the ischial spine and deepest point, all measured variables of the greater sciatic notch were greater for women than men on both sides. The length of the posterior segment and the posterior angle on both sides showed the highest positive correlation and provided highly significant differences between males and females. These findings not only reinforce the utility of the greater sciatic notch in sex determination but also highlight the potential for more accurate and noninvasive methods in forensic investigations.ConclusionsPostmortem computed tomography accurately determines sex by measuring the posterior sciatic notch segment, achieving a 90.9% accuracy rate. This study, the first of its kind in India, utilized postmortem computed tomography ruler measurements for sex determination, specifically evaluating the role of the posterior segment dimensions of the greater sciatic notch in the North Indian population.

Bridging the notch: quantification of the end diastolic notch to better predict fetal growth restriction.

We aimed to evaluate several quantitative methods to describe the diastolic notch (DN) and compare their performance in the prediction of fetal growth restriction. Patients who underwent a placental scan at 16-26 weeks of gestation and delivered between Jan 2016 and Dec 2020 were included. The uterine artery pulsatility index was measured for all of the patients. In patients with a DN, it was quantified using the notch index and notch depth index. Odds ratios for small for gestational age neonates (defined as birth weight <10th and <5th percentile) were calculated. Predictive values of uterine artery pulsatility, notch, and notch depth index for fetal growth restriction were calculated. Overall, 514 patients were included, with 69 (13.4%) of them delivering a small for gestational age neonate (birth weight<10th percentile). Of these, 20 (20.9%) had a mean uterine artery pulsatility index >95th percentile, 13 (18.8%) had a unilateral notch, and 11 (15.9%) had a bilateral notch. 16 patients (23.2%) had both a high uterine artery pulsatility index (>95th percentile) and a diastolic notch. Comparison of the performance between uterine artery pulsatility, notch, and notch depth index using receiver operating characteristic curves to predict fetal growth restriction <10th percentile found area under the curve values of 0.659, 0.679, and 0.704, respectively, with overlapping confidence intervals. Quantifying the diastolic notch at 16-26 weeks of gestation did not provide any added benefit in terms of prediction of neonatal birth weight below the 10th or 5th percentile for gestational age, compared with uterine artery pulsatility index.

Inverse design and optimization of an aperiodic multi-notch fiber Bragg grating using neural networks

Recent developments in the application of aperiodic fiber Bragg gratings (AFBGs) in astrophotonics, such as AFBG for astronomical near-infrared OH suppression and gas detection based on cross-correlation spectroscopy, have illuminated the problem that the optimization for AFBG with certain fabrication constraints has not been fully investigated and solved. Previous solutions will either sacrifice part of the spectral features or consume a significant amount of computation resources and time. Inspired by recently successful applications of artificial neural networks (ANNs) in photonics inverse design, we develop an AFBG optimization approach employing ANNs in conjunction with genetic algorithms (GAs) for the first time, to the best of our knowledge. The approach maintains the spectral notch depths and preserves the fourth-order super-Gaussian spectral features with improvements of interline loss by ∼100 times. We also implement, to our knowledge, the first inverse scattering neural network based on a tandem architecture for AFBG, using a first-order Gaussian notch profile. The neural network successfully converges but has a poor predictive capability for the phase part of the design. We discuss possible ways to overcome these limitations.

Initiation and growth of fatigue cracks in sheets with U-shaped notches in the first and mixed modes of fracture

Initiation and growth of fatigue cracks in sheets with U-shaped notches in the first and mixed modes of fracture

Enhanced accuracy and high sensitivity in dielectric characterization through a compact and miniaturized metamaterial inspired microwave sensor

This academic paper introduces a novel sensor known as the Planar Microstrip-based Triple Ring Bridge Complementary Split Ring Resonator (TRB-CSRR) sensor. The main objective of this sensor is to determine the permittivity and thickness of solid dielectric substances. The TRB-CSRR sensor is meticulously designed to resonate precisely at a frequency of 4.86 GHz, achieving a significant notch depth of −33.5 dB. This configuration displays an enhanced average relative sensitivity of 20.2%. The study undertakes numerical assessments across various scenarios, encompassing situations where the sensor interacts with diverse dielectric materials. These assessments yield insights into alterations in resonant frequencies. By meticulously refining the design, the sensor's capability to confine electric fields precisely at the resonant frequency is amplified, ultimately resulting in heightened sensitivity towards dielectric characteristics. The sensor's efficacy is tested using materials featuring relative permittivity values spanning from 1.006 to 12.9, while consistently adhering to dimensions of 5 mm×5 mm×1.6 mm. To validate the conceptual frame-work, a physical sensor is fabricated, and its response is gauged through the utilization of a vector network analyzer (VNA-AV3672D). Employing curve fitting methodologies, alterations in resonance frequencies due to interactions with the tested materials are presented, underscoring the impact of permittivity and thickness. The outcomes derived from simulations, empirical measurements, and calculations display a robust alignment.