Method For Measurement Of Rate Research Articles

Development of a non-invasive heart rate measurement method for sea turtles with dense keratinous scutes through effective electrode placement.

Measuring the heart rate of sea turtles is important for understanding their physiological adaptations to the environment. Non-invasive methods to measure the electrocardiogram (ECG) of sea turtles have been developed by attaching electrodes to their carapace. However, this method has only been applicable to sea turtles with sparse keratin on their shell surfaces, such as loggerhead turtles, and it is difficult to detect heartbeats in sea turtles with dense keratinous scutes, including green sea turtles. Here, we explored the electrode placements on the plastron that can be applied to ECG measurement in green turtles. ECG signals were checked using a handheld ECG monitor at three sets of electrode placement on the plastron. When ECG signals could be detected, they were measured in the water tanks for several days to confirm the clarity of the ECG signals. Of the 29 green turtles, when the negative electrode was placed near the neck area of the plastron, clear ECG signals were obtained in nine individuals (39.1%), whereas ECG signals were not detected at any placements in four individuals (17.4%). Furthermore, in the water tank experiments, continuous ECG signals were successfully recorded by attaching a negative electrode near the neck: almost noiseless clear ECG signals even during moving in seven out of ten individuals and slightly weak and noisy signals in other individuals. The measured heart rate of ten individuals during resting was 8.6 ± 2.9 (means ± s.d.) beats min-1 and that during moving was 12.2 ± 4.7 beats min-1, similar to those reported in a previous study involving the insertion of electrodes inside the body. Therefore, for measuring the ECG of green turtles, the negative electrode should be placed closer to the neck, and the positive and earth electrodes should be placed to the lower left of the plastron. Although the selection of suitable individuals for measurements is required, this heart rate measurement method will contribute to a better understanding of the physiological status of sea turtles with dense keratinous scutes, including green turtles.

Closed-Loop Method for Accurate Measurement of Rn-220 Exhalation Rate from Soil Surfaces

Closed-Loop Method for Accurate Measurement of Rn-220 Exhalation Rate from Soil Surfaces

Investigation of the Effect of Compression Force on the Tensile Strength and Infiltration Rate of Pervious Concrete Blocks

Pervious concrete is widely used as a paving material. Pervious pavement is generally constructed by pouring fresh pervious concrete and compacting. However, it has some difficulties such as finishing and curing. In addition, the road has to be closed, until the pervious concrete gains enough strength. Pervious concrete block is a new material that can overcome these difficulties. In this study, the effect of compression force on the strength and infiltration rate of pervious concrete blocks has been investigated. The compaction process was different from traditional methods in this study, and was applied according to predesignated compression forces on fresh pervious concrete mixtures sensitively. Within the scope of the study, 36 different mixtures were produced by applying four different compression forces (25, 50, 75, and 100 kN) in three different sample thicknesses (60, 80, and 100 mm) with three different aggregate sizes (2–4, 4–8, and 8–16 mm). As a result, it was found that while the increase in the compression force increases the splitting tensile strength of pervious concrete blocks with 2–4 and 4–8 mm aggregate, it causes a decrease in the strength due to the aggregate crushing phenomenon in mixtures with 8–16 mm aggregate, 6 cm thick samples. In this study, it was seen that the expectation that the increase in compaction would always cause an increase in strength is not valid, contrary to the literature. The infiltration rate decreased as the compression force increased, as expected. It was determined that the new infiltration rate measurement method has been found effective. Considering the strength requirement in the TS 2824 EN 1338 standard, pervious concrete blocks produced with 4–8 mm aggregate, compressed with 75 kN force and having 80 mm thickness have been determined as the optimum block type.

Rain Fade Analysis on High Frequency Signal: A Review

A reliable transmission of high-frequency signal of more than 10 GHz is crucial for various communication systems, especially in the era of advanced technologies and wireless communications. Rain-induced signal fades pose a significant challenge to signal integrity, making accurate rain rate measurement methods essential for system optimization. This review critically examines the existing techniques for measuring rain rate and the applicability in analysing high-frequency signal fades. Several case studies and practical examples are presented to illustrate the significance of accurate rain rate measurements in predicting and mitigating signal degradation. Researchers are working to enhance existing models to better fit local environmental variables based on all the case studies. Having an accurate estimation of the level of rain attenuation in the signal is one of the components to ensuring the quality of service of a communication signal. Signal availability can be ensured with suitable rain attenuation modelling, assuming that all other communication elements are functioning as planned.

Characterization of fatigue crack growth in directed energy deposited Ti-6Al-4V by marker load method

Fatigue crack growth properties of materials are crucial for evaluating damage tolerance in additive manufacturing (AM) metallic structures. However, the unique microstructures and defects of AM materials result in highly complex fatigue crack growth behaviors. Currently, there is a lack of systematic fatigue crack growth rate measurement methods specifically targeting this characteristic. Therefore, taking directed energy deposited Ti-6Al-4V titanium alloy as the object of the study, fatigue crack growth tests were conducted in three orthogonal build orientations of the material using marker load method. Additionally, the visual measurement and compliance methods were also employed to measure fatigue crack growth rates, and the anisotropy of fatigue crack growth property was analyzed. Subsequently, anisotropic fatigue crack growth behaviors were characterized by optical microscope, scanning electron microscope, confocal microscope, and electron backscatter diffraction, suggesting that the microstructure is the primary factor affecting overall fatigue crack growth. Furthermore, nanoindentation tests were conducted to obtain the micromechanical properties within and among columnar grains in different build orientations, clarifying the homogeneity and anisotropy of mechanical properties. Finally, a fatigue crack growth rate measurement method based on marker load method was established, and the advantages of this method in AM materials and structures were summarized by comparing the results with those obtained using these two mature methods.

Arch formation mechanism and discharge process of cohesive fine powder in a vibrated silo

The arch formation mechanism and discharge process of a very cohesive fine powder (calcium carbonate) in a vibrated silo was investigated by experiments and discrete element method (DEM) simulations. An experimental setup is built to study the flow behaviors with the proposed image-based flow rate measurement method. A cohesive DEM model is used to investigate the dynamic behaviors of the powder bed. Results indicate that the arch formation depends on the vibration acceleration amplitude and is slightly affected by the frequency. The powder discharge flow rate increases with vibration acceleration amplitude and decreases with frequency. When the acceleration amplitude exceeds 15 g, the flow rate tends to stabilize. When the acceleration amplitude exceeds 1 g, there is separation and collision between the powder bed and the silo bottom. This collision leads to a significant increase in the contact force.

Comparative analysis of basal metabolic rate measurement methods in overweight and obese individuals: A retrospective study.

The global prevalence of overweight and obesity is on the rise, presenting significant health challenges worldwide. Obesity is associated with various chronic diseases and imposes substantial economic burdens on society. Accurate assessment of basal metabolic rate (BMR) is crucial for effective weight management strategies. This retrospective study, conducted at Baskent University Hospital between October 2019 and October 2023, analyzed data from 133 overweight and obese individuals. Various methods including indirect calorimetry (IC), predictive equations (Harris-Benedict and Mifflin-St Jeor), and bioelectrical impedance analysis (BIA) were used to estimate BMR. Additionally, demographic, clinical, and body composition data were recorded. The mean BMR measured using IC was 1581 ± 322 kcal/day, which was significantly lower than the BMR estimated by other methods such as BIA (1765.8 ± 344.09 kcal/day), Harris-Benedict (1787.64 ± 341.4 kcal/day), and Mifflin-St Jeor equations (1690.08 ± 296.36 kcal/day) (P < .001). Among the predictive equations, the Mifflin-St Jeor method provided BMR estimates closest to the gold standard IC. When BMR measurement methods were compared to IC, 36.8% of measurements with the Harris-Benedict equation method, 50.4% with the Mifflin-St Jeor equation method, and 36.1% with the BIA method were within ± 10% agreement with IC measurements. Significant correlations were found between BMR and body composition parameters such as fat-free mass, muscle mass, and fat mass (R = 0.681, P < .001; R = 0.699, P < .001; R = 0.595, P < .001, respectively). Regression analysis identified that variables such as weight, height, body mass index, and muscle mass significantly predicted BMR measured by IC, accounting for 69.1% of the variance. This study underscores the challenges in assessing BMR in overweight and obese individuals. While IC remains the gold standard, predictive equations and BIA offer alternative methods. The Mifflin-St Jeor equation emerged as a practical option, closely aligning with IC results. However, discrepancies between methods and the influence of body composition highlight the importance of individualized approaches to BMR assessment in weight management strategies.

Near-Infrared-Based Measurement Method of Mass Flow Rate in Grain Vibration Feeding System

The radial distribution of material feeding onto a screen surface is an important factor affecting vibration screening performance, and it is also the main basis for the optimization of the operating parameters of a vibration screening system. In this paper, based on near-infrared properties, a real-time measurement method for the mass flow rate of grain vibration feeding was proposed. A laser emitter and a silicon photocell were used as the measuring components, and the corresponding signal processing circuit mainly composed of a T-type I/V convertor, a voltage follower, a low-pass filter, and a setting circuit in series was designed. Calibration test results showed that the relationship between grain mass flow rate and output voltage could be described using the Gaussian regression model, and the coefficient of determination was greater than 0.98. According to the working principle of the grain cleaning system of combine harvesters, the dynamic characteristics of grain vibration feeding were analyzed using discrete element method (DEM) simulations, and the monitoring range of the sensor was determined. Finally, grain mass flow rate measurement tests were carried out on a vibration feeding test rig. The results indicated that the grain mass measurement error could be controlled within 5.0% with the average grain mass flow rate in the range of 3.0–5.0 g/mm·s. The proposed measurement method has potential application value in the uniform feeding control systems of vibration feeders.

The measurement method of solvent evaporation rate of photoresist liquid film based on monochromatic light interference

The measurement method of solvent evaporation rate of photoresist liquid film based on monochromatic light interference

Method for Two-Stage Radar Measurement of the Blade Repetition Rate of a Propeller-Driven Aircraft

Introduction. Radar images of aircraft propellers can significantly improve the quality of their recognition and protection against simulating interference. Such images can be obtained using algorithms based on an inverse antenna aperture synthesis. A key factor determining the quality of image acquisition is the accuracy of the rotor blade rotation frequency measurement. In 2019, a method for measuring the blade repetition rate was proposed, which is based on convolution of the "secondary" signal modulation spectrum while simultaneously eliminating the influence of the Doppler frequency of the signal reflected from the aircraft body. In sequential analysis, the number of cycles is determined by the ratio of the maximum blade repetition rate (hundreds of hertz) to the discrete frequency shift (thousandths of hertz). In this case, to solve the measurement problem, the required number of cycles should be hundreds of thousands, which is expensive in terms of practical implementation.Aim. Development of a two-stage method for measuring the blade repetition rate, which allows the number of signal convolution cycles to be reduced by hundreds of times.Materials and methods. The proposed method is aimed at implementing adaptation circuits to an a priori unknown rotor speed of an aircraft, which can be determined based on the blade rotation frequency. The method involves measuring the blade frequency in two stages: a rough measurement of the blade frequency rate followed by its accurate measurement within the limits of the maximum errors of the rough measurement.Results. A method for a two-stage measurement of the blade repetition rate as applied to the construction of radar images of aircraft propellers is proposed. The feasibility of the method is illustrated by the example of a signal reflected from a Mi-8 helicopter. The requirements to the measurement error of the blade repetition rate and to the frequency analysis step at the precise measurement stage are formulated. The requirement to the repetition rate of probing signals is substantiated, the fulfillment of which ensures an unambiguous restoration of the spectrum of "secondary" modulation of the signal reflected from the blades of a propeller-driven aircraft.Conclusion. The developed method for a two-stage measurement of the blade repetition rate ensures the adaptation of algorithms for constructing radar images of aircraft propellers to their rotation frequency.

Updates in Chronic Kidney Disease.

Chronic kidney disease (CKD) affects approximately 14% of adults in the United States and is present in at least 10% of the population worldwide. Blood glucose and blood pressure control are imperative to adequately manage CKD as they are the only primary prevention measures for the condition. Recent changes in CKD evaluation and medication therapies that modify disease progression and aid in managing complications such as anemia of CKD have emerged, including a newly approved mineralocorticoid receptor antagonist and hypoxia-inducible factor-prolyl hydroxylase inhibitor, respectively. This focused update on CKD evaluation and management will review the most recent evidence and approved agents to support patients with CKD, including a review of glomerular filtration rate measurement methods such as CKD-EPI 2021 and utilization of cystatin C, Kidney Disease Improving Global Outcomes (KDIGO) guidelines, American Diabetes Association (ADA) guidelines, and primary literature supporting the use of newer agents in CKD. Checklists for managing blood pressure and blood glucose, CKD-mineral bone disorder, and anemia of CKD targeted for pharmacists are also provided. Additionally, a discussion of Centers for Medicare & Medicaid (CMS) coverage of agents approved for managing complications of CKD is included.

A Novel Remote-Tracking Heart Rate Measurement Method Based on Stepping Motor and mm-Wave FMCW Radar

A Novel Remote-Tracking Heart Rate Measurement Method Based on Stepping Motor and mm-Wave FMCW Radar

Effects of strain rate and bedding on shale fracture mechanisms

Anisotropic shale is commonly distributed in nature and undergoes both dynamic compressive and tensile load in geological engineering. In this article, the coupling effects of strain rate and bedding structures on the fracture mechanisms of shale are investigated using a split Hopkinson pressure bar (SHPB) system. The tension–compression comparative study is conducted. The Brazilian disc method is modified, and a unified strain rate measurement method is established to comprehensively analyze shale’s fracture-related properties, including moduli, strength and energy dissipation. The results indicate that the energy dissipated by shale fracture is strongly related to its strength. The strain rate and bedding affect the anisotropic strength and dissipated energy by changing the crack density and crack propagation mode. At low or medium strain rates, the bedding orientation of shale determines the direction of crack propagation. However, at high strain rates, microcracks in different directions are widely activated in the shale, which increases the fracture degree and decreases the difference in fracture toughness between the shale’s matrix and bedding planes. This also leads to a decrease in anisotropy and causes the bedding planes to lose control over the direction of crack propagation. Additionally, the dynamic tensile strength of shale increases faster than the compressive one with the strain rate, leading to a reduction in the proportion of tensile failure under impact load. Based on the experimental findings, a new anisotropic damage constitutive model is developed to characterize the dynamic properties of shale. This model reflects the anisotropic damage evolution behaviors and aligns well with experimental results, offering a theoretical foundation for predicting shale’s dynamic fracture behavior. In addition to shale, the developed experimental methods and theoretical models can also be applied to the fracture analysis of other brittle transversely isotropic materials.

A review of investigation of the metabolic rate effects on human thermal comfort

The precise analysis of the usage of thermal indices to evaluate and create an acceptable space is a research hotspot as thermal comfort increasingly comes to be the center of attention. The accurate measurement and calculation of the metabolic rate should be a top priority in research because it is the most important component of thermal indexmodels. This study includes a literature survey of the relevant fields to properly comprehend the present developments and flaws in calculating the metabolic rate. The ultimate objective is to apply the growth of human metabolic science to logical urban development. First, the interaction between the thermal environment and thermal comfort was analyzed, and then, the influence of the human metabolic rate on thermal comfort was discussed. The results show that the dynamic change of metabolic rate is the key human factor that directly affects the thermal regulation, and indirectly affects the evaluation accuracy of the thermal evaluation index standard. Through an inductive analysis of metabolic rate measurement methods that are widely used in various environments, this study identifies several issues with the current utilization of portable metabolic monitoring instruments in dynamic thermal comfort research, highlighting their limitations in addressing accuracy, portability, economy, and other relevant aspects. An essential future effort in this study path will be the continued research and development of a more portable, more affordable, more direct, and more efficient customized metabolic rate monitoring equipment. In addition, the fact that metabolic rate is represented as a constant or its impact on thermal comfort as a single factor in existing thermal index models also frequently results in incorrect findings in outdoor research. The fundamental condition for enhancing thermal comfort index forecast accuracy is accurate and continuous tracking of metabolic rate.

A comparative study of porosity rate measurement methods and influence of energy density in Inconel 718 produced by laser powder bed fusion additive manufacturing process

A comparative study of porosity rate measurement methods and influence of energy density in Inconel 718 produced by laser powder bed fusion additive manufacturing process

Low-cost cultivation of Nannochloropsis oceanica in newly designed photobioreactors and its productivity trends in semi-continuous cultivation under inland outdoor conditions

Most marine microalgae are typically cultivated in coastal areas due to challenges in inland cultivation. In this 185 days experiment, Nannochloropsis oceanica was semi-continuously cultivated inland using different photobioreactors (PBRs). The newly designed 700-liter (L) PBR exhibited tolerance to seasonal changes compared to the 150-L PBRs. The innovative in-situ oxygen release rate (ORR) measurement method results indicated that ORR was influenced by light intensity and temperature. The optimal temperature range for N. oceanica growth was 14–25 ℃, demonstrated cold tolerance and lipid accumulation at low temperatures. The maximum lipid content in 700-L and 150-L PBRs was 29 % and 28 %, respectively. Based on the average biomass productivity, the price of N. oceanica was $11.89 kg−1 (or $3.35 kg−1 based on maximum biomass productivity), which is cheaper than the current market price of $20.19 kg−1. From results, smaller PBRs at the same hydro electricity price are more cost-effective.

Analysis and Compensation of Lorentz Force Magnetic Bearing Magnetic Flux Density Uniformity Error.

Aiming at the influence of the magnetic flux density uniformity error (MFDUE) of the Lorentz force magnetic bearing (LFMB) on the sensitivity accuracy of magnetically suspended control and sensing gyroscopes (MSCSGs) on the angular rate of a spacecraft, a high precision measurement method of the angular rate of a spacecraft based on the MFDUE compensation of LFMB is proposed. Firstly, the structure of MSCSG and the sensitivity principle of MSCSG to the spacecraft angular rate are introduced. The mechanism influencing the accuracy of MSCSG to spacecraft angular rate sensitivity is deduced based on the definition of magnetic flux density uniformity. Secondly, the 3D magnetic flux distribution of LFMB is analyzed using ANSYS. The relationship between the rotor tilt angle, tilt angular rate, and magnetic flux density is established. The induced current calculation model due to MFDUE is proposed, and the LFMB magnetic flux density error compensation is realized. Finally, the simulation results show that the estimation accuracy of the induced current by the proposed method can reach 96%, and the simulation and the experiment show that the error compensation method can improve the accuracy of MSCSG in measuring the spacecraft angular rate by 12.5%.

Synchronized measurement method of burning rate and combustion temperature of a solid propellant specimen

To characterize the combustion properties of solid propellants, the synchronized measurement method of burning rate and combustion temperature is proposed combined shadow imaging and radiation imaging. Using spectroscopic and filtering imaging, shadow and radiation images of a solid propellant specimen are obtained synchronously. Burning rate is calculated by burning surface movement velocity of shadow images, and combustion temperature is calculated by radiation image thermometry. Measurement accuracies of burning rate and combustion temperature of the solid propellant specimen are validated by other independent measurement methods. On this basis, the synchronized measurements of burning rate and combustion temperature of different formulations of solid propellant specimens under different working conditions are carried out. The results show that the influence on burning rate and combustion temperature of pressure and formulas is different. Therefore, the synchronized measurement of burning rate and combustion temperature can provide more direct data support for the evaluation of solid propellant combustion performance.

A novel flow rate measurement method for fire hose based on vibration signal and neural network

During fire incidents, it is imperative to monitor the flow rate of the fire hoses. Due to the constraints imposed by the fire scene, vibration-based flow measurement technique has shown great potential. However, usage of single frequency or statistic feature to predict flow rate is prone to influenced by outer noise. In this study, we constructed a dataset for fire-hose flow rate prediction task with a flow rate range of 0.35 L/s to 20.00 L/s, and sample frequency of 50 kHz. On that basis, a new variant of residual network, i.e., an RBU-STMS has been developed, integrating soft thresholding and feature pyramid mechanism. Evaluation result on the dataset has proven the effectiveness of the developed model which yields improvement of 3.85 % and 4.05 % by incorporating the two mechanisms individually and an overall improvement of 5.00 % by combining both mechanisms, compared to the conventional residual network. Furthermore, the proposed model exhibits a considerable tolerance to noisy inputs, with a predicted error rate of only 8.06 % when subjected to a 10 % standard deviation of random noise in the input, remaining below the 10 % threshold.

CalibrationPhys: Self-Supervised Video-Based Heart and Respiratory Rate Measurements by Calibrating Between Multiple Cameras.

Video-based heart and respiratory rate measurements using facial videos are more useful and user-friendly than traditional contact-based sensors. However, most of the current deep learning approaches require ground-truth pulse and respiratory waves for model training, which are expensive to collect. In this paper, we propose CalibrationPhys, a self-supervised video-based heart and respiratory rate measurement method that calibrates between multiple cameras. CalibrationPhys trains deep learning models without supervised labels by using facial videos captured simultaneously by multiple cameras. Contrastive learning is performed so that the pulse and respiratory waves predicted from the synchronized videos using multiple cameras are positive and those from different videos are negative. CalibrationPhys also improves the robustness of the models by means of a data augmentation technique and successfully leverages a pre-trained model for a particular camera. Experimental results utilizing two datasets demonstrate that CalibrationPhys outperforms state-of-the-art heart and respiratory rate measurement methods. Since we optimize camera-specific models using only videos from multiple cameras, our approach makes it easy to use arbitrary cameras for heart and respiratory rate measurements.