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In this paper, a novel methodology is presented to evaluate the true nonlinear shear response of continuous fiber-reinforced plastic (CFRP) unidirectional laminae. It requires simple off-axis tensile experiments to be conducted and a finite element (FE) representation of them with a material constitutive law capable of handling nonlinearity in shear. Upon successful evaluation of the normal stiffness properties, the shear stress-strain response is derived via numerical calibration of the underlying FE models. The presented approach is also demonstrated by processing the raw data of an extensive material characterization test campaign conducted on a thermoplastic matrix CFRP. The outcome is compared to the conventional methods for shear response derivation using relevant standards such as ASTM D3518 and ASTM D5379. It has been successfully demonstrated that the pseudo-hardening phenomenon obtained from standard shear experiments as a result of fibers aligning with load direction can be eliminated with off-axis specimen tension experiments, thus, the true shear stress versus deformation response can be extracted up to failure. The main purpose of current work is to demonstrate the inconsistency in the available standard methods related to mechanical testing-based derivation of nonlinear in-plane shear behavior of UD plies. In addition, a novel technique is presented to achieve a more accurate prediction of nonlinear shear stress and strain along the entire representative loading range that contributes to more accurate simulations of composite parts up to failure and thus, better strength predictions. [ABSTRACT FROM AUTHOR]

FT-IR spectroscopy is the basic finger-print method for qualitative and quantitative analysis of nitrogen, boron, and hydrogen impurities in natural and synthetic diamonds. In quantitative measurements of impurity concentrations, external standard samples are required for the calibration procedure during the analysis. In this study, the double-phonon mid-IR absorption coefficient of optical phonons of the diamond host matrix, the robust internal mid-IR absorption standard, was accurately measured for tens of diverse diamond samples, thus enabling precise calibrated measurements of ultra-low detectable impurity concentrations.

Background: Early childhood caries (ECC) requires systematically collected and standardized data., Aim: To describe a novel multilevel calibration procedure in primary dentition., Design: Calibration method involved two calibration levels: the first (L 1 ) involved an interexaminer agreement between three main investigators, the group leaders (GLs) in the following level; the second level (L 2 ) involved three groups of 11 paediatric dentists and interexaminer agreement assessment according to the GLs in each group. The study sample consisted of 650 primary teeth surfaces in eight children (mean age 6.56 ± 2.22 years). Surface-by-surface percent agreement, tooth-by-tooth percent agreement, Cohen's kappa, and Fleiss kappa statistics were used to calculate interexaminer reliability. Statistical analysis was performed with SPSS 27.0., Results: Surface-by-surface percent agreement regarding ICDASepi-merged revealed almost perfect agreement (>90.00%) on both L 1 and L 2 . Kappa values and ranges showed good agreement at both L 1 (overall κ = .95) and L 2 (overall κ = .98) and almost perfect consistency was detected between GLs at L 1 (>91.30%) and substantial agreement at L 2 (>85.00%). All examiners at L 2 showed almost perfect positive agreement (sensitivity = 96.77%-100%) when detecting the presence of dental plaque., Conclusion: The calibration procedure appeared feasible prior to organizing multicenter epidemiological oral health survey in large population groups of preschool children, with higher number of examiners., (© 2023 The Authors. International Journal of Paediatric Dentistry published by BSPD, IAPD and John Wiley & Sons Ltd.)

With zoom lenses, both the magnification of the camera and the distance between the lens and the object plane can be changed. Changes to zoom lens magnification is accompanied by changes in the depth of field and the distance between the lens and the object plane, complicating the calibration of zoom cameras—specifically, that of each focus and zoom control, for which separate configurations are required. To overcome this problem, a procedure for the calibration of a multifocus zoom lens in a three-dimensional (3D) scanning system was developed in the present study. Specifically, a pragmatic, five-step calibration procedure was proposed. In the first two steps, the characteristics of the zoom lens were obtained. In the third and fourth steps, the calibration was normalized. Finally, the effectiveness of the process was assessed using a laboratory-developed prototype. High reconstruction accuracy was achieved.

Accurate medical Augmented Reality (AR) rendering requires two calibrations, a camera intrinsic matrix estimation and a hand-eye transformation. We present a unified, practical, marker-less, real-time system to estimate both these transformations during surgery. For camera calibration we perform calibrations at multiple distances from the endoscope, pre-operatively, to parametrize the camera intrinsic matrix as a function of distance from the endoscope. Then, we retrieve the camera parameters intra-operatively by estimating the distance of the surgical site from the endoscope in less than 1 s. Unlike in prior work, our method does not require the endoscope to be taken out of the patient; for the hand-eye calibration, as opposed to conventional methods that require the identification of a marker, we make use of a rendered tool-tip in 3D. As the surgeon moves the instrument and observes the offset between the actual and the rendered tool-tip, they can select points of high visual error and manually bring the instrument tip to match the virtual rendered tool tip. To evaluate the hand-eye calibration, 5 subjects carried out the hand-eye calibration procedure on a da Vinci robot. Average Target Registration Error of approximately 7mm was achieved with just three data points.

Barometric process separation (BaPS) is an automated laboratory system for the simultaneous measurement of microbial respiration and gross nitrification rates in soil samples. To ensure optimal functioning, the sensor system, consisting of a pressure sensor, an O2 sensor, a CO2 concentration sensor, and two temperature probes, must be accurately calibrated. For the regular on-site quality control of the sensors, we developed easy, inexpensive, and flexible calibration procedures. The pressure sensor was calibrated by means of a differential manometer. The O2 and CO2 sensors were simultaneously calibrated through their exposure to a sequence of O2 and CO2 concentrations obtained by sequentially exchanging O2/N2 and CO2/N2 calibration gases. Linear regression models were best suited for describing the recorded calibration data. The accuracy of O2 and CO2 calibration was mainly affected by the accuracy of the utilized gas mixtures. Because the applied measuring method is based on the O2 conductivity of ZrO2, the O2 sensor is particularly susceptible to aging and to consequent signal shifts. Sensor signals were characterized by high temporal stability over the years. Deviations in the calibration parameters affected the measured gross nitrification rate by up to 12.5% and affected the respiration rate by up to 5%. Overall, the proposed calibration procedures are valuable tools for ensuring the quality of BaPS measurements and for promptly identifying sensor malfunctions.