A dissolved inorganic carbon measurement method featured self-calibration function via an electrodialytic generator

A simple dissolved inorganic carbon (DIC) measurment method featured self-calibration function via an electrodialytic bicarbonate eluent generator (cEDG) is described. It is based on gas diffusion flow analysis system that...

Online harmonic error compensation of Atan2 function for a low-cost automotive sensor application

A new compensation method of harmonic distortions by using Atan2 function is introduced in this paper. It provides a simple online calibration function to determine the parameters of harmonic distortions. Thus, it can be implemented in a microcontroller with less computational capacity and can increase the accuracy of a low-cost angle position sensor for automotive applications.

Quantitative, Temperature-Calibrated, and Real-Time Glucose Biosensor Based on Symmetrical-Meandering-Type Resistor and Intertwined Capacitor Structure

Here, we propose a glucose biosensor with the advantages of quantification, excellent linearity, temperature-calibration function, and real-time detection based on a resistor and capacitor, in which the resistor works as a temperature sensor and the capacitor works as a biosensor. The resistor has a symmetrical meandering type structure that increases the contact area, leading to variations in resistance and effective temperature monitoring of a glucose solution. The capacitor is designed with an intertwined structure that fully contacts the glucose solution, so that capacitance is sensitively varied, and high sensitivity monitoring can be realized. Moreover, a polydimethylsiloxane microfluidic channel is applied to achieve a fixed shape, a fixed point, and quantitative measurements, which can eliminate influences caused by fluidity, shape, and thickness of the glucose sample. The glucose solution in a temperature range of 25–100 °C is measured with variations of 0.2716 Ω/°C and a linearity response of 0.9993, ensuring that the capacitor sensor can have reference temperature information before detecting the glucose concentration, achieving the purpose of temperature calibration. The proposed capacitor-based biosensor demonstrates sensitivities of 0.413 nF/mg·dL−1, 0.048 nF/mg·dL−1, and 0.011 pF/mg·dL−1; linearity responses of 0.96039, 0.91547, and 0.97835; and response times less than 1 second, respectively, at DC, 1 kHz, and 1 MHz for a glucose solution with a concentration range of 25–1000 mg/dL.

The influence of the Earth’s magnetic field on strapdown inertial gravimetry using Q-Flex accelerometers: static and dynamic experiments

In recent strapdown airborne and shipborne gravimetry campaigns with servo accelerometers of the widely used Q-Flex type, results have been impaired by heading-dependent measurement errors. This paper shows that the effect is, in all likelihood, caused by the sensitivity of the Q-Flex type sensor to the Earth’s magnetic field. In order to assess the influence of magnetic fields on the utilised strapdown IMU of the type iMAR iNAV-RQH-1003, the IMU has been exposed to various magnetic fields of known directions and intensities in a 3-D Helmholtz coil. Based on the results, a calibration function for the vertical accelerometer is developed. At the example of five shipborne and airborne campaigns, it is outlined that under specific circumstances the precision of the gravimetry results can be strongly improved using the magnetic calibration approach: The non-adjusted RMSE at repeated lines decreased from 1.19 to 0.26 mGal at a shipborne campaign at Lake Müritz, Germany. To the knowledge of the authors, a significant influence of the Earth’s magnetic field on strapdown inertial gravimetry is demonstrated for the first time.

Determination of energy parameters of seismic events of the Transcarpathian trough taking into account the quality factor of the Earth’s crust

Transcarpathia is characterized by significant differences in the structure and geodynamics of the lithosphere in comparison with other seismically active regions of Ukraine, which causes a number of features of the seismotectonic process of this region. The spatial distribution of the seismicity of the Transcarpathian Depression is closely related to the fault-block structure of the foundation. Important characteristics of the seismic process in Transcarpathia are the energy parameters of local earthquakes — magnitude, intensity, energy class. It is these values that form the basis of seismic zoning. The methods used to determine the energy parameters of local earthquakes do not fully take into account the effects of hypocenter depths and regional features of seismic wave propagation paths. Thus, the issue of determining the quantitative indicators of the quality factor of the Earth’s crust of the studied region and the development of approaches to determining the calibration function for estimating local magnitudes is relevant. The article presents the results of the study, which are aimed at determining the calibration function for calculating the energy characteristics of earthquakes in the Transcarpathian Depression, taking into account the parameters of attenuation of the Earth’s crust. Using digital records of seismic signals from the Transcarpathian Depression, obtained on the elements of the Ukrainian seismic group, as well as seismic stations «Stone Bridge», «Pidluby», «Zelenytsia» and «Lyubar» were determined quantitative indicators of the quality of the Earth’s crust and developed approaches to determination of the calibration function for estimation of local magnitude and its check on real signals.

Geologically calibrated mammalian tree and the corresponding global events, including birth of human

The robust timetree could be constructed using a calibration function of BEAST v1. X released in 2018 simply by applying times of the most recent (= the latest) common ancestors (tMRCAs) for specific monophyletic species groups (clades). The present research is probably the first trial to fully use the calibration function in BEAST X. The specific node age (child tMRCA) in BEAST X = “minimum age” in conventional MCMCTree, but the “maximum age” in MCMCTree can be equivalent to, e.g., the parent node age (parent tMRCA) in BEAST X. We applied 19 mammalian fossil calibration ages considering Benton et al. (2015; solely their minimum ages), including those of fossil Gorilla and Pan + one geologic event calibration age for otters (= Quaternary isolation time of the Ryukyu islands and start of vicariant speciation), and we estimated our targeted splitting age of Homo and Pan at 5.69 Ma (calibration dates by Benton et al., 2015 were incorrect). After the initial rifting at 120 Ma, the Atlantic Ocean spread over 500 km on Chron 34 (84 Ma), and Afrotheria (Africa) and Xenarthra (South America) started vicariant speciation at this time (~ 70 Ma), reflecting the progressed continental isolation. Ordinal-level differentiations started just after the K-Pg boundary (66.0 Ma), and this timing reconfirmed that mammalian radiation occurred by rapidly filling the niches left vacant by the non-avian dinosaurs. In addition, we made a base substitution rate vs age diagram using the BEAST X function and showed that the rate exponentially increased and accelerated toward the Holocene, other than having the 55 Ma mild peak reflecting the post K-Pg mammalian explosion. The increased rate might have consequently increased the biodiversity, and extensive adaptive radiation might have ultimately birthed Homo sapiens. The basic factor of radiation might be the generation and spreading of C4 grasses since 20 Ma, which has been linked to increasing carbon fixation, decreasing atmospheric CO2 concentrations, cooling Earth, and triggering the Quaternary (2.58 Ma ~) glacier-inter glacier cycle and severe climatic change. Note that Perissodactyla and Cetartiodactyla (Laurasiatheria) feed on C4 grasses (savanna), and Carnivora (also Laurasiatheria) is the predator, also suggesting coevolutions since 20 Ma.

Numerical and Experimental Fracture Mechanical Investigations of Clinchable Sheet Metals Made of HCT590X

In many areas of product manufacturing constructions consist of individual components and metal sheets that are joined together to form complex structures. A simple and industrial common method for joining dissimilar and coated materials is clinching. During the joining process and due to the service load cracks can occur in the area of the joint, propagate due to cyclic loading and consequently lead to structural failure. For the prevention of these damage cases, first of all knowledge about the fracture mechanical material parameters regarding the original material state of the sheet metals used within the clinching process are essential.Within the scope of this paper experimental and numerical preliminary investigations regarding the fracture mechanical behavior of sheet metals used within the clinching process are presented. Due to the low thickness of 1.5 mm of the material sheets, the development of a new specimen is necessary to determine the crack growth rate curve including the fracture mechanical parameters like the threshold against crack growth ΔKI,th and the fracture toughness KIC of the base material HCT590X. For the experimental determination of the crack growth rate curve the numerical calculation of the geometry factor function as well as the calibration function of this special specimen are essential. After the experimental validation of the numerically determined calibration function, crack growth rate curves are determined for the stress ratios R = 0.1 and R = 0.3 to examine the mean stress sensitivity. In addition, the different rolling directions of 0° and 90° in relation to the initial crack are taken into account in order to investigate the influence of the anisotropy due to rolling.

Calibrating Hall-Effect valvometers accounting for electromagnetic properties of the sensor and dynamic geometry of the bivalves shell

Hall-Effect valvometry (HES) is being used to describe bivalve valve gape variations and infer environmental perturbations in a variety of aquatic environments. Surprisingly, the published calibrations in ecological literature ignore both the electromagnetic properties of HES and that the valves rotate around their hinge when they move. The high sensitivity of HES suggests these features should be accounted for explicitly to estimate measurement accurately. To address these issues, two calibration functions were developed based on the electromagnetic properties of the HES: one assumes that the HES and magnet are maintained on the same linear axis, and the second model accounts for the geometric properties of the system (i.e. variations of the angle between HES and the magnet during shell rotation). The great scallop (Pecten maximus) was used as biological model because of its large range of valve openings. HES were installed on the flat valve and magnets installed on the opposing rounded valve; 12 individuals of similar size (10 ± 1(SD) cm), were equipped and placed in controlled experimental conditions. A calibration was done for each individual once time series recordings were completed. The variability of parameter estimates was calculated with a bootstrap method. The second model (with rotatation) improves valve gape distance estimates for larger openings despite the decrease of sensor sensitivity. To infer valve gape dynamics, the reciprocal calculation of the calibration function was formalized and applied to the Hall voltage time series. Our analysis suggests that under controlled laboratory conditions, scallops are partially open most of the time (inter-valve distance equal ca. 27 mm on average, or 45 % of the average maximum opening distance). Interspersed in this continuous regime, individual scallops performed closing events at a frequency of ca. 2.5 closings per hour. A closing event is a movement that is fast enough relative to the recording frequency (10 Hz) to qualify as discrete. We find that the inversed calibration model without rotation allows negative value estimates, which indicates that this calibration function is incorrect. In contrast, the inversed calibration model with valve rotation around the hinge constrains gape distance values in their domain of definition which automatically excludes sensor readings that produce negative values from estimated gape time series.

Cicada timetree by BEAST v1.X verified the recently and exponentially increasing base substitution rates

Following the recent publication of global cicada phylogenetic trees by Marshall et al. (2018), Łukasik et al. (2018), and Simon et al. (2019), we developed a new dated tree incorporating mostly endemic east Asian cicada data for totally 113 specimens, using the mostly advanced BEAST v1.X software applied the relaxed clock model. Fossil calibrations as old as Triassic were adopted after Moulds (2018), and a Quaternary geological event calibration was adopted following Osozawa et al. (2012), applying the calibration function of BEAST. Our timetree suggests that Tettigarctidae had cicada basal lineage as old as 200 Ma, and Derotettiginae was next as old as 100 Ma. Tibicininae was a sister of the resting Cicadidae, and Tettigomyiinae, Cicadettinae, and Cicadina started simultaneous branching and radiation around 40 Ma. We made a base substitution rate vs age diagram based on the timetree using the BEAST function, and it strongly suggested an exponential increase of base substitution rate approaching the present. The consequent increased cicada biodiversity including generation of cryptic species might have been driven by the generation and spreading of C4 grasses and the following Quaternary glaciations and severe environmental change.