Calibration Tests Research Articles

Monitoring Technology of Surrounding Rock Deformation Based on IWFBG Sensing Principle and Its Application

Abstract To address the challenge of achieving precise real-time monitoring of significant deformation in deep roadway surrounding rock, a quasi-distributed strain-sensing cable (SSC), which has a spatial resolution of 1 m, was developed based on the principle of Identical Weak Fiber Bragg Gratings. The performance of SSC has been evaluated through a series of calibration tests, revealing a range of 0%–3%, an accuracy level of 0.5%, a strain sensitivity measuring at 1.23 pm/με, and a temperature sensitivity recorded as 10.78 pm/℃. Furthermore, a real-time deformation monitoring system has been established to monitor rock deformation, consisting of SSC, supporting installation equipment, demodulation equipment, and monitoring software. Moreover, the proposed methodology was applied in the deep roadway of Guqiao coal mine. The results showed that the maximum surface displacement of the roadway is 103.47 mm, while the lateral contrast error stands at 5%. The maximum strain value of the surrounding rock measures 27,095 με. The depth of rock rupture zone is about 3 m, while the boundary of rock damage zone extends up to 6 m. This information serves as the foundation for determining the parameters of the roadway reinforcement support design.

Experimental study of the influence factors of the droplet size of rotary nozzles during manned helicopter spraying operations

The droplet size significantly affects the performance of aerial spraying operations. Thus, it is crucial to develop rotary nozzles for helicopter spraying operations and analyze the influence of droplet size. We conducted a calibration test of the nozzle rotation speed to analyze the effects of air velocity, blade installation angle, hub diameter, and blade length on the rotation speed. The results showed that the rotation speed increased with an increase in air velocity and nozzle diameter and decreased with an increase in the blade angle. The rotation speed of three types of rotary nozzles was measured in the range of 576–15 358 r/min. A high-speed wind tunnel test was conducted to determine the droplet size of the rotary nozzles at different rotation speeds, spray flow rates, and hub mesh numbers. The influence degree of the three factors on the droplet size was rotation speed > spray flow rate > mesh number. The multiple linear regression equation of the volume median diameter (VMD) of the droplet size was obtained. The droplet size obtained from wind tunnel and flight tests at 5000 and 7000 r/min was compared. The droplet size was in the range of 148.56–259.39 μm and was slightly larger under wind tunnel conditions than during the flight test. The relative width of the droplet spectrum was small for both test methods, indicating that the droplet size distribution of the three rotary nozzles was uniform. Finally, the spray nozzles were used for insect control in forest areas and achieved a control efficiency of 94.6. This study provides a reference for optimizing the operating parameters of spraying nozzles and improving the performance of helicopter-based low-volume spraying operations.

Research on the Mechanical Properties and Temperature Compensation of an Intelligent Pot Bearing for a Pipe-Type Welding Strain Gauge.

As an important component connecting the upper and lower structures of a bridge, bridge bearings can reliably transfer vertical and horizontal loads to a foundation. Bearing capacity needs to be monitored during construction and maintenance. To create an intelligent pot bearing, a portable small spot welding machine is used to weld pipe-type welding strain gauges to the pot bearing to measure strain and force values. The research contents of this paper include the finite element analysis of a basin bearing, optimal arrangement of welding strain gauges, calibration testing, and temperature compensation testing of the intelligent basin bearing of the welding strain gauges. Polynomial fitting is used for the fitting and analysis of test data. The results indicate that the developed intelligent pot bearing has a high-precision force measurement function and that after temperature compensation, the measurement error is within 1.8%. The intelligent pot bearing has a low production cost, and the pipe-type welding strain gauges can be conveniently replaced. The novelty is that the bearing adopts a robust pipe-type welding strain gauge and that automatic temperature compensation is used. Therefore, the research results have excellent engineering application value.

Pelaksanaan Quality Control Pesawat Sinar X di Pelayanan Radiodiagnostik

Background: Quality Control can be used as a monitoring of the reliability of X-Ray Unit during the validity period of the Conformity Test Certificate. During the use of X-ray Unit, there is the potential for damage to components during the validity period of the certificate of passing the Compliance Test. If the X-Ray Unit Reliability Test is only carried out during the Compliance Test, then if there is a decrease in the quality and safety of the X-ray Unit it cannot be immediately known. This has the potential to endanger patients, radiation workers and the public. In Banyumas Regency, there are 80 Radiation Source Utilization Permits spread across 34 radiodiagnostic installation. Preliminary studies show that not all radiodiagnostic installation carry out routine X-ray machine reliability tests according to the Keputusan Menteri Kesehatan Republik Indonesia Nomor 1250/Menkes/SK/XII/2009 Tentang Pedoman Kendali Mutu (Quality Control) Peralatan Radiodiagnostik.
 Method: This research type is qualitative with survey of 20 radiodiagnostic installation using a questionnaire instrument. Quality control conducted periodically includes kVp accuracy test, linearity and reproducibility mA, exposure time accuracy test, tube leak test, collimator beam suitability test, collimator shutter efficiency test, collimator light strength test, HVL measurement, implementation of reject analysis program and availability and qualifications of quality control officers and availability of quality control equipment. Then the data will be grouped based on research objectives and presented descriptively.
 Result: From the results of data collection, 1 hospital did not have a quality control officer and 4 hospitals had a quality control officer with an educational background of Diploma IV in Radiology Engineering without any Radiology Equipment Quality Control training. Meanwhile, 15 hospitals have quality control officers with an educational background in the Medical Physics Undergraduate Program and have attended training in Quality Control of Radiology Equipment. Of the 20 hospital radiology installations, there were 7 hospitals that did not carry out the Reject Analysis Program. This was done with the assumption that Digital Radiography had been used in both the CR and DR modalities. A number of 13 hospitals continued to carry out the Reject Analysis Program even though they had used Digital Radiography. Of the 20 hospital radiology installations, there are 6 hospitals that independently carry out X-ray unit testing within the framework of a quality control program. However, only 1 hospital conducts regular testing. Testing is also limited to the accuracy of the collimator field and the strong light of the collimator. Fourteen hospitals did not carry out a quality control program independently but only carried out an X-ray unit calibration test once a year which was carried out by BPFK and an X-ray unit distributor company.
 Conclusion: The implementation of quality control of x-ray machines on a regular basis has not been carried out by all radiodiagnostic services, even though they already have quality control officers. One of the reasons is the availability of quality control equipment needed for testing and supervision of radiodiagnostic service management. The role of management of radiodiagnostic services is needed to overcome these problems.
 
 Keyword : Quality Control Programe, Compliance Test, X-Ray Unit

APACHE IV, SAPS III, and SOFA scores for outcome prediction in a surgical/trauma critical care unit: an analytical cross-sectional study

BackgroundPatients’ outcomes in surgical/trauma intensive care units (ICUs) are still challenging to predict. There has been a lack of consensus over the efficacy of Acute Physiology and Chronic Health Evaluation IV (APACHE IV), Simplified Acute Physiology Score III (SAPS III), and Sequential Organ Failure Assessment (SOFA) scores in predicting patient outcomes. This analytical cross-sectional study was designed to determine how well APACHE IV, SAPS III, and SOFA scores predict ICU mortality and the length of stay in a surgical ICU. APACHE IV, SAPS III, and SOFA scores were calculated on admission. The effectiveness of these scores in predicting mortality was determined using logistic regression models. The accuracy of these discriminative abilities was measured using the area under the receiver operating characteristic curve (AUC). The Hosmer and Lemeshow calibration test was calculated to test the model fit. The agreement between APACHE IV, SAPS III, and SOFA scores in the prediction of mortality was examined using the Bland–Altman curve.ResultsA total of 148 patients met the study criteria. APACHE IV was the only significant predictor of mortality, with a 1-point increase in the APACHE IV score resulting in a 5% increase in death probability (AOR = 1.049, 95% CI 1.028–1.069) (P-value < 0.001). The APACHE IV score was superior to the SAPS III and SOFA scores regarding accuracy, with an AUC of 0.766 (95% CI, 0.670–0.862) (P-value < 0.001). Furthermore, there was a significant positive correlation between APACHE IV score and ICU length of stay (r = 0.22, P = 0.004).ConclusionAPACHE IV outperformed SAPS III and SOFA scores in predicting mortality in a surgical/trauma critical care unit and showed a significant positive correlation with the ICU length of stay.

2D of Robotic Arm Based on Inverse Kinematics Using Arduino

Abstract: The advancements and quick developments in the technology has made it possible to create a platform for the invention of new as well as great things. One of the concept that is being used lately to improve the technology is the concept of robotics. This project focuses on the implementation of inverse kinematics for a 2-DOF (two degrees of freedom) robot arm using an Arduino microcontroller. The inverse kinematics equations are derived and programmed to calculate the joint angles required to position the robot arm's end effector in a desired location within its workspace. The Arduino board is used to interface with the robot arm's actuators and control the movement of the arm. The Arduino programming aspect of the project involves developing a control algorithm that accepts target coordinates for the end effector and computes the necessary joint angles using inverse kinematics equations. Servo motors are manipulated through the Arduino Servo library to achieve the calculated angles, enabling the arm to reach the desired positions accurately and efficiently. To enhance the functionality and safety of the 2-DOF robotic arm, the project includes features such as calibration routines, testing procedures, and safety measures to avoid collisions and servo load. The project aims to demonstrate the application of inverse kinematics in controlling robotic manipulators for precise positioning tasks

Design and Experimental Results of a Three-Dimensional Force Sensor for Shearer Cutting Pick Force Monitoring

The main focus of this work is the design and development of a three-dimensional force sensor for the cutting pick of a coal mining shearer’s simulated drum. This sensor is capable of simultaneously measuring the magnitude of force along three directions of the cutting pick during the cutting sample process. The three-dimensional force sensor is built based on the strain theory of material mechanics, and reasonable structural design is implemented to improve its sensitivity and reduce inter-axis coupling errors. The strain distribution of the sensor is analyzed using finite element analysis software, and the distribution of the strain gauges is determined based on the analysis results. In addition, a calibration test system is designed for the sensor, and the sensitivity, linearity, and inter-axis coupling errors of the sensor are calibrated and tested using loading experiments in three mutually perpendicular directions. Modal simulation analysis and actual cutting pick testing of the coal mining machine’s simulated drum are conducted to study the dynamic characteristics and functionality of the sensor in practical applications. The experimental results depict sensitivities of 0.748 mV/V, 2.367 mV/V, and 2.83 mV/V for the newly developed sensor, respectively. Furthermore, the cross-sensitivity error was lower than 5.02%. These findings validate that the sensor’s structure satisfies the measurement requirements for pick-cutting forces.

Intercomparison of Landsat OLI and JPSS VIIRS Using a Combination of RadCalNet Sites as a Common Reference

Independent radiometric data collected from multiple ground sites as part of vicarious calibration activities can be combined to harmonize the data products of Earth observation sensors with different temporal, spectral, and spatial resolutions. Recent coordinated international efforts for open fiducial reference measurements have provided the worldwide user community with new ways to explore the calibration and harmonization of data produced by the sensors. To be correct, the results from each ground system must be traceable to the same well-understood standard system, and ideally to the international system of units (SI). Additionally, the calibration test site should be homogeneous over an area larger than the spatial resolutions of each sensor, so that ground measurements are representative of the area seen by the sensors being calibrated. Here, we use a combination of independent and SI-traceable radiometric data provided from two sites of the Radiometric Calibration Network (RadCalNet) to compare the radiometric response of sensors with different spectral and spatial resolutions that operate on different orbits. These sensors are Operational Land Imagers (OLI) of the Landsat-8 and Landsat-9 missions, and Visible Infrared Imaging Radiometer Suites (VIIRS) of the Suomi-National Polar-Orbiting Operational Environmental Satellite System Preparatory Project (SNPP) and Joint Polar Satellite System-1 (JPSS-1) missions. The sensor radiometric responses are compared via temporal averaging of the ratios of top-of-atmosphere reflectance values for each sensor to those reported by RadCalNet. Our intercomparison results show that these on-orbit sensors are calibrated within their absolute radiometric uncertainties. The absolute radiometric uncertainties of single-sensor over single-site intercomparisons at 550 nm is between 5% and 6%. Having the opportunity to look at the intercomparison results of Landsat-9 OLI compared to each calibration site individually and then in combination allowed us to investigate potential systematic site-dependent biases. We did not observe significant site-dependent biases in the behavior of the four on-orbit sensors compared to the calibration sites. The absolute radiometric uncertainty of a single sensor over multiple-site intercomparisons at 550 nm is 5.4%. We further investigated site-dependent biases by looking at the double-ratio calibration coefficients of the on-orbit sensors, calculated with reference to those sites.

Development and validation of a predictive tool for adverse drug reactions in neonates under intensive care.

Neonates hospitalized in neonatal intensive care units (NICUs) commonly experience adverse drug reactions (ADRs). Thus, we aimed to develop and validate a tool for predicting ADRs in neonates hospitalized in NICUs. A nested case-control study in an open cohort with neonates admitted to the NICU of a maternity hospital in Natal, Brazil was conducted from January 2019 to January 2022 [Correction added on 4 December 2023, after first online publication: 2023 has been changed to 2019 in the preceding sentence.]. Neonates with ADR were randomly paired with 2 controls. For the development of the tool, a multivariate logistic regression was applied on 2/3 of the sample (cases with respective controls). The model's fit was evaluated using the Hosmer-Lemeshow test for calibration and the Brier score for performance assessment. Validation of the tool was performed by determining the area under the receiver operating characteristic curve with bootstrap adjusted c-statistics. In all, 450 neonates (150 cases and 300 controls) were included in the study. We identified 5 independent risk factors for ADR, 4 related to the neonate (current mechanical ventilation, heart rate ≥178 beats/min, intravenous medications, ≥5 prescription medications) and 1 to the mother (gestational hypertension). The tool had a classification cut-off point of ≥15, and its total score ranged from 0 to 34. In validation, the tool had an area under the receiver operating characteristic curve of 0.74 (95% confidence interval [CI] 0.66-0.81) with sensitivity of 52.02% (95% CI 47.40-56.64) and specificity of 81.35% (95% CI 77.75-84.95). The tool demonstrated adequate discriminative ability and utilized 5 commonly monitored variables in the NICU.

Fine alignment, flexible fusion: A novel framework of multi-model score fusion in face identification

Multi-model score fusion was considered a bottleneck problem in forensic face identification. While the score distribution of different face models varies greatly, the existing score processing methods cannot achieve accurate alignment. This paper proposed a score fusion framework named fine alignment and flexible fusion framework (FAFF). In FAFF, we took score-based likelihood ratios as the reference values to align the similarity scores generated by different face models. First, we set up a unified calibration test workflow based on the forensic likelihood ratio test. Then, 3 LLR anchor-based methods (LLRBA1, LLRBA2, and LLRBA3) and LLR curve-based methods (LLRBC) were proposed. Finally, we conducted fusion experiments on four face models (VGGface, Facenet, Arcface, and SFace). The experimental results show that on the CelebA dataset, compared with the existing MOEBA and PAN methods, LLRBC increased the TPR@ 10−7 FPR by 175.4 % and 162.9 %, and LLRBA increased by 55.6 % and 48.5 %.

Structural Design and Optimization of the Milling Force Measurement Tool System Embedded with Thin-Film Strain Sensors.

A milling force measurement tool system is designed with an elastic beam structure, which is divided into a two-end ring hoop compression sensor mode and a two-end square hoop compression sensor mode to improve the strain sensitivity. A simplified mechanical model of the elastic beam is established, and the relationship between the strain and force of the elastic beam under the action of three cutting force components is investigated, which can act a guide for subsequent milling force measurement tool system calibration tests. Thin-film strain sensors occupy a central position in the milling force measurement tool system, which consists of a substrate, transition layer, insulating layer and resistance grid layer. The resistance grid layer has a particularly significant effect on the thin-film strain sensor's performance. In order to further improve the sensitivity of thin-film strain sensors, the shapes of the substrate, the transition layer, the insulating layer and the resistance grid layer are optimized and studied. A new thin-film strain sensor is designed with a resistance grid beam constructed from an insulating layer and a resistive grid layer double-end-supported on the transition layer. The flow of the wet-etching process of thin-film strain sensors is studied and samples are obtained. The surface microforms of the sensor samples are observed by extended depth-of-field microscopy, confocal microscopy and atomic force microscopy. It can be seen that the boundary of the resistance grid layer pattern is tidy and has high dimensional accuracy, thus enabling the basic achievement of the expected effect of the design. The electrical performance of the samples is tested on an experimental platform that we built, and the results show that the resistive sensitivity coefficient of the samples is increased by about 20%, to 51.2%, compared with that of the flat thin-film strain sensor, which fulfils the design's requirements.

Research on the Prediction Method of Clock Tester Calibration Data Based on Radial Basis Function Neural Network

A radial basis function (RBF) neural network-based calibration data prediction model for clock testers is proposed to address the issues of fixed calibration cycles, low efficiency, and waste of electrical energy. This provides a new method for clock tester traceability calibration. First, analyze the mechanism of clock tester calibration parameters and the influencing factors of prediction targets. Based on the learning rules of an RBF neural network, determine the data types of training and testing sets. Second, normalize the training and testing data to avoid the adverse effects of data characteristics and distribution differences on the prediction model. Finally, based on different prediction objectives, time-driven and data-driven calibration data prediction models are constructed using RBF neural networks. Through simulation analysis, it is shown that an RBF neural network is superior to a BP neural network in predicting clock tester calibration data, and time-driven prediction accuracy is superior to data-driven prediction accuracy. Moreover, the prediction error and mean square error of both prediction models are on the order of 10−9, meeting the prediction accuracy requirements.

ВИЗНАЧЕННЯ ТА ВРАХУВАННЯ СИСТЕМАТИЧНИХ ПОХИБОК ПРИ ВИМІРЮВАННІ НАВІГАЦІЙНИХ ГЛИБИН

The scientific study considers the issue of studying the features and determining the inherent values of systematic errors that occur when measuring navigation depths with multibeam echosounders, the elimination of these errors from the measurement results, which requires a special organization and methodology for performing multibeam echosounders tests. Systematic errors of navigation data can affect as on the magnitude of the depth itself, as well as on its planned position, and their influence should be evaluated after studying the angular measurements by echo sounder beams and calibration. The calibration of multi-beam systems, as well as the horizontal and vertical movements of the vessel, is much more significant and complicated compared to the calibration of single-beam systems. It is necessary to perform system accuracy control tests to confirm the reliability of multibeam echosounder data. These tests should preferably be carried out on board before taking depth measurements. For this, it is necessary to capture data, process and edit them in real time. Periodic performance of accurate calibration and testing is necessary to confirm that the multibeam survey meets the accuracy requirements. Multibeam echosounders calibration tests are performed with the aim of minimizing errors, taking into account the delay time of data acquisition, sea waves and changes in the ship's course. Keywords: multibeam echosounder, systematic errors, sensor calibration, hydrographic surveys, relief of the seabed, marine navigation chart, measured tacks, survey software.

Plasma Analyzer for the Chinese FY-3E Satellite: In-Orbit Performance and Ground Calibration

The plasma analyzer (PMA) on the Fengyun-3E (FY-3E) meteorological satellite series is a critical sensor of the space environment monitoring package that is capable of the comprehensive in situ detection of the thermal plasma environment and surface discharge effects. In this paper, we conducted a thorough evaluation of the PMA’s performance and reliability through a combination of ground-based laboratory calibration and in-orbit testing. During the ground-based calibration, the PMA underwent assessments for the energy range, field of view (FOV), and measurement accuracy, and obtained the detection accuracy and the geometric factors. During the in-orbit testing, the PMA successfully obtained the typical distribution characteristics of low-energy ions and electrons in orbital space regions, as well as the precipitating particles in the middle and high latitudes of both hemispheres. Notably, the PMA observed an expansion of the particle distribution in the high-latitude regions during a moderate geomagnetic storm. The results from both the ground-based calibration and in-orbit testing demonstrated that the PMA met the requirements for thermal plasma detection, with reliable and scientifically valid in-orbit detection data. These results provide a crucial foundation for studying spatial weather variations, improving the accuracy of space environment forecasts and enhancing disaster detection and monitoring capabilities.

Phosphor thermometry evaluation of heat transfer enhancement on a hot plate achieved by a vortex-based fluidic oscillator

Recently, a vortex-based feedback fluidic oscillator has been proposed as an alternative to conventional feedback fluidic oscillators. This study aimed to compare the heat transfer performance of a newly designed fluidic oscillator with that of conventional feedback fluidic oscillators with and without an output diffuser using phosphor thermometry. To obtain the instantaneous temperature field in a wide range of high temperatures, a lifetime-based method was employed in two-dimensional phosphor thermography, with Mg4FGeO6: Mn serving as the sensor material and being excited by a UV-LED. A high-speed camera was used to capture images of the hot plate at 4,000 fps. The calibration test was conducted in the temperature range of 25–325 ˚C, and the results were compared with data from thermocouples. The study investigated the impact of the mass flow rate and throat-to-plate distance ratio of three fluidic oscillators to obtain the optimum Nusselt number. The results demonstrated that the newly designed fluidic oscillator exhibited significantly superior cooling effects in comparison to other types of fluidic oscillators. At the lowest ratio of the throat-to-wall distance to the outlet throat height (Z/D = 4.5) and a flow rate of 100 Lpm, the vortex-based fluidic oscillator demonstrated 78 % and 45 % higher heat transfer rates compared to the conventional oscillator with and without an external diffuser, respectively. Furthermore, the newly designed oscillator was more sensitive to the mass flow rate and throat-to-plate distance ratio than the other oscillators.

High-Temperature Failure Evolution Analysis of K-Type Film Thermocouples.

Ni90%Cr10% and Ni97%Si3% thin-film thermocouples (TFTCs) were fabricated on a silicon substrate using magnetron sputtering technology. Static calibration yielded a Seebeck coefficient of 23.00 μV/°C. During staged temperature elevation of the TFTCs while continuously monitoring their thermoelectric output, a rapid decline in thermoelectric potential was observed upon the hot junction reaching 600 °C; the device had failed. Through three cycles of repetitive static calibration tests ranging from room temperature to 500 °C, it was observed that the thermoelectric performance of the TFTCs deteriorated as the testing progressed. Utilizing the same methodology, Ni-Cr and Ni-Si thin films corresponding to the positive and negative electrodes of the TFTCs were prepared. Their resistivity after undergoing various temperature annealing treatments was measured. Additionally, their surfaces were characterized using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The causes behind the decline in thermoelectric performance at elevated temperatures were analyzed from both chemical composition and microstructural perspectives.

Determination of Multicomponents in Rubi Fructus by Near-Infrared Spectroscopy Technique

Objective. Rubi Fructus (RF) is a dry aggregate fruit of Rubus (Rosaceae). It has shown significant pharmacological effects such as anti-oxidation, hypoglycemic, and anti-inflammatory. A combination of near-infrared (NIR) spectroscopy and partial least squares regression (PLSR) under seven different spectral data preprocessing techniques was used to determine the performance of quantitative analysis correction models which employed moisure, ellagic acid, and total flavonoids as indicators of RF. Methods. Ninety-seven different RF batches were collected for NIR spectra. By using primary analysis techniques such as drying method, high-performance liquid chromatography (HPLC), and ultraviolet visible spectrophotometry (UV-Vis), the contents of moisure, ellagic acid, and total flavonoids were determined. The NIR spectral data and the primary analysis method data were correlated through PLSR. Seven methods were used for pretreating the spectral data, including no spectral pretreatment, first derivative, standard normalized variate, multiple scattering corrections, elimination of constant offset, and minimum maximum normalization. The quantitative analysis correction models adopted PLSR chemometrics for moisture, ellagic acid and total flavonoids were developed, and their effectiveness was evaluated using the correlation coefficient (R), ratio of prediction to deviation (RPD), and root mean square error (RMSE). Results. The first derivative was combined with variable standardization, elimination of constant offset, and multiple scattering corrections, respectively, to pretreat the PLSR models for moisture, ellagic acid, and total flavonoids. The R-values of the PLSR models for moisture, ellagic acid, and total flavonoids were, respectively, 0.9788, 0.9468, and 0.9748, all of which were higher than 0.90, and the RPD values were 4.9, 3.1, and 4.5, respectively, which were all larger than 3.0. The RMSE ratios of the calibration set and the test set were 0.98, 0.94, and 1.0, respectively. Conclusion. The R-values of the NIR-PLSR models for moisture, ellagic acid, and total flavonoids are all greater than 0.90 after suitable pretreatments, indicating that the models are reliable. The RPD values are more than 3.0, which indicate that the models are good and useable for quality control. The RMSE ratios are closed to 1, indicating that the calibration set and test set had same distribution and the models were not overfitting indicating good predictability.

Smart control of soil water and salt content for improving irrigation management of tomato crop field: Kairouan area.

A good assessment of soil water and salt content is required for sustainable irrigation with brackish/saline water. The use of the Internet of Things (IoT) has been initiated for the tomato crop (Savera variety) as part of the PRIMA MEDITOMATO project. An experiment was carried out between February and June 2022 at a farmer's site. For continuous soil water and salt content assessment, TEROS (11/12) probes were implemented at depths of 0, 10, 20, 30, and 60 cm. The data logging process was performed by a ZL6 device and delivered by the ZENTRA Cloud web application (METER GROUPE Company). For the accuracy of the introduced sensors, calibration tests were first processed. Results of the calibration of the probes in the laboratory and in situ showed linear relationships between the humidity values measured by ZL6 (θZL6) and those determined by the gravimetric method, with high correlation coefficients (R2) of 0.86 and 0.96, respectively. There were also strong linear relationships between the ECbulk(ZL6) and the ECe measured on saturated paste extract with high correlation coefficients (R2) of 0.96 and 0.95. Corrected data, according to the determined linear regression equations, present the real-time assessment of soil water and salt content over the entire growth stage of tomatoes. The results of this monitoring showed that soil water content remained close to its status at field capacity (32%) at the beginning of the assessment and increased with the intensification of irrigation, reaching 46 and 54% at 20 and 30 cm, respectively, around mid-April. The salinity level was greater with depth. Indeed, it was low in topsoil with the increase in irrigation frequency and higher at 30 and 60 cm toward the end of the tomato cycle. According to this study, real-time data given by ZENTRA Cloud allows us to adjust irrigation management on time.

Modified hybrid damage criterion for the cross wedge rolling process

This paper considers the problem of material fracture in the cross wedge rolling (CWR) process. A modification of the hybrid damage criterion dedicated to crack prediction in CWR was proposed. The aim of the modification was to make the limits of the new criterion independent of the implementation temperature of the calibration tests. A rotary compression test was carried out to obtain specimens in which cracking is initiated. Based on the analysis of the FE results of the rotary compression test simulation, the final version of the modified hybrid damage criterion (MHDC) was presented. Using the results of experimental tests and FE simulations, the MHDC limit values were determined. The MHDC limits for the three different temperatures were obtained at similar levels, indicating that the MHDC limits can be made independent of the rotary compression test execution temperature. The MHDC was verified on the example of the cross wedge rolling of a railway axle forging. The verification carried out confirmed the possibility of predicting cracks in CWR-rolled forgings using MHDC. The research results obtained are of an applied nature. In particular, the criterion developed can be helpful in the design of cross wedge rolling technology.

Developed log-wake law and turbulent behaviour of flow along a stepped spillway

Abstract The log-wake law for turbulent current has been developed and tested with laboratory data on turbulent flow in smooth pipes. However, flow with turbulence and vortices in a stepped spillway have not been described. Therefore, in this study, a log-wake law has been developed for use in stepped spillway systems. It can be divided into three parts. The first part, a logarithmic equation, describes the effect of shear stress between the flow layers with a von Kármán constant of 0.41. The second part, a third-degree polynomial, describes the effect of the shear stress on the wall. The last part, a fourth-degree polynomial, describes the effect of changing the flow pressure distribution, similar to the wall-free shear stress. Calibration tests (68 datasets) are used with a flow rate between 0.0233 and 3.285 m3/s, a spillway slope of 14–30°, and a step height of 0.0380–0.610 m. The developed log-wake law characterized the flow in a stepped spillway well. The limitation of the equation is a maximum flow velocity of 4 m/s; the accuracy of this equation decreases as the step height increases.