Probe Rod Research Articles

DETERMINATION OF HEAT TRANSFER CONDITIONS WHEN COOLING A HIGH-TEMPERATURE SURFACE

The solution of inverse heat conduction problems for the identification of parameters of mathematical models is of particular importance for ensuring the adequacy of these models in the presence of experimental information about the thermal process under study. The effectiveness of decisions made when designing various power equipment depends both on the depth and reliability of knowledge of heat exchange phenomena and on the adequacy of modeling various thermophysical processes. In order to create effective methods for diagnosing and identifying such processes, experimental studies are conducted and their results are processed. These methods can be based on solutions of inverse problems of heat conduction for both homogeneous and composite media. In some cases, methods for solving inverse problems are the only means of obtaining the necessary information about the object under study. This paper presents a mathematical model for determining the temperature field of a specially designed thermal probe rod and a method for solving the boundary inverse problem of thermal conductivity (BIP), which is reduced to determining heat flows and heat transfer coefficients based on experimental temperature measurements at one or more internal points. The value of the heat flow and the heat transfer coefficient at the working end of the thermoprobe rod when it is cooled by liquid will be determined as a result of solving the OZT. The solution itself will be performed by a direct method, and its implementation will be carried out numerically.

Time domain reflectometry coil probes for measuring thin surface layer soil moisture: Field tests over 21 years (2002–2022) under highly variable climate conditions in Mongolia

A coil probe (CP) for time-domain reflectometry (TDR) with a sensor length of 40 mm (CP40) was developed for long-term field soil moisture measurements in a thin surface soil layer (0–3 cm depth). In laboratory, soil moisture measurements of CP40 were nearly identical to those of a traditional two-rod type TDR (2RTDR) probe (rod length: 15 cm, diameter: 0.3 cm, spacing: 3 cm). The CP40 measurement accuracy was between 0.01 m3/m3 and 0.03 m3/m3. For long-term field soil moisture measurements, five CP40 units were installed in the highly wetted soil at the Sanzai site (SS), which is in the permafrost area of the Taiga, and dry soil at the Mandalgobi site (MGS) in the semi-arid area of Mongolia. Four units accurately measured soil moisture at both sites over six years (2002–2007and 2008–2009). Three units succeeded in conducting precisely continuous soil moisture measurements between 2008 and 2022 at the MGS. Two units successfully measured soil moisture over 21 years at both the sites. The representativeness of the CP40 soil moisture measurements in highly wetted soils was low because of heavy rainfall and soil heterogeneity. The accuracy of CP40 soil moisture measurements in highly wetted soils was slightly lower than that of the traditional 2RTDR probe. However, the accuracy of the CP40 soil-moisture measurements in the dry soil was comparable to that of the traditional 2RTDR probe. CP40 units are durable and their field soil moisture measurements demonstrate stable and precise performance (bias, RMSE), even under severe environmental conditions.

Pore form and size dependence on plastic joining characteristics of resin/metallic foam by friction stir incremental forming

A metallic foam specimen was plastically joined with a resin (polymethyl methacrylate, PMMA) sheet by applying friction stir incremental forming (FSIF) process. In FSIF process, a rotating flat-ended (no probe) rod tool was pushed vertically and fed horizontally against the resin sheet which was placed on the foam. The tool operation heated frictionally the resin and deformed incrementally to the resin, while the tool operation did not deform plastically to the cellular matrix of the foam. Due to the plastic flow of the heated resin, the bottom of the resin was interlocked mechanically to the pores near the top surface of the foam. In this study, the relationship between the pore morphology (form and size) and the joining characteristics (joinability, flow thickness of the resin, and joining strength) was investigated using commercial open-cell nickel and closed-cell aluminum foams. According to the experimental investigations, the foam with small size and low depression angle of the surface pore showed better results in relation with the joining strength and the (flow thickness of the resin)/(depth of the surface pore).

Model prediction controller for penetration mechanism of seabed cone penetration test system

The system of seabed Cone Penetration Test (CPT) is a kind of equipment for offshore investigations. Seabed CPT is used to assess multiple physical properties of marine sediments. Constant-rate penetration mechanism is the core part of seabed CPT, which adopts dual-cylinder drive to penetrate the probe rod into the seafloor sediments at a constant speed (2cm/s). At present, the domestic CPT and its penetration equipment almost all rely on imports. In the process of system design, we found that the traditional PID control of the hydraulic cylinder position control accuracy is low, so we need to study higher precision position tracking control method to achieve uniform penetration of the probe rod. In this paper, a Linear Time-Varying Model Predictive Controller (LTV-MPC) is introduced, which can control two hydraulic cylinders to penetrate probe rod into the seabed sediment with smaller penetration rate error under the condition of changing penetration resistance.

Uniplanar multirod TDR probe for soil water content measurement over a larger spatial scale

AbstractThis study developed a uniplanar multirod time domain reflectometry (TDR) probe and evaluated it in laboratory experiments for soil water measurement over a larger spatial scale. The sampling volume of the probe was determined by simulating the electric potential distribution around the probe rods by using the HYDRUS‐2D software package and verified by comparison with the measured dielectric constant in saturated sand. The performance of the probe was evaluated by comparing its dielectric measurements in wet sand over a wide range of water content during evaporative drying with that measured by CS640 probes. Additionally, the dependency of visible light reflection on the water content of the sand was evaluated. The results revealed that the average effective thickness of the probe's sampling volume was 5–6 cm on both sides of the plane of the probe rods. The probe accurately measured the soil water content over a 0.88 m2 spatial area. The visible light reflectance of the variably saturated sand surface and the corresponding water content of the sand follow a soil water retention function‐type relationship. The usage of the multirod TDR measurement system at a larger spatial scale carries practical implications, especially in increasing the accuracy of remote sensing data.

Experimental Study on Axial Stress and Hammer Impacting Energy of Offshore Standard Penetration Test

Standard penetration test (SPT) has been widely used in offshore exploration because of its unique advantages. Unlike onshore exploration, offshore construction areas are characterized by high waves and water depths ranging from several meters to tens of meters. As a result, the reliability of offshore SPT is significantly reduced compared with onshore SPT. Currently, the probe rod length correction of SPT is not involved in geotechnical engineering investigation codes and related research, which greatly limits the application of this method in offshore exploration. Therefore, a series of SPTs were carried out in offshore environments with different water depths, with a maximum rod length of 65 m. The acceleration and axial stress at each test point of the rod were monitored by the dynamic signal data acquisition system, and the hammer impacting energy at each test point was obtained by Force–Velocity (F-V) method. The test results show that the correction of the rod length of the offshore SPT is different from that of the traditional SPT, and it needs to be further corrected for the water depth. In this paper, a modified method of rod length for offshore SPT is proposed, which can provide reference for the application of offshore SPT.

Analysis and research on the constant-rate penetration mechanism of the seabed cone penetration test system

The seabed Cone Penetration Test (CPT) system is a common method for investigating offshore soil. This paper focuses on a new subsea CPT method for assessing physical and mechanical properties of marine sediments. The new method enables automatic docking and dismantling of the probe rods underwater. The constant-rate penetration mechanism is the basis and core component of the seabed CPT, allowing the probe rod and cone to penetrate the seafloor sediment. Double hydraulic cylinders are used to meet the high penetration force requirements. To maintain a constant penetration rate of 20 ± 5 mm/s, the model identification of the electro-hydraulic servo system is performed using Simcenter AMESim and MATLAB software, and the relevant transfer function is obtained using the PID method. Based on this transfer function, the sliding mode variable structure controller of the electro-hydraulic servo system is designed to regulate the constant penetration rate of the hydraulic cylinder against varying penetration resistance. In-situ measurements were operated using the new seabed CPT rig in Zhoushan Island. The simulation and testing results confirm that the sliding mode variable structure controller is suitable for controlling the system during actual operation.

Measurement method and experimental study on the intrusion resistance of coal slurry/wet pulverized coal

ABSTRACT Coal slurry is a semi-solid material formed by the water content of pulverized coal, which is a product of the coal production and transportation process and has viscous and wet characteristics, and is easy to cause blockage in the process of mechanized mining and transportation. To study the resistance law of the probe rod pressed into the quasi-static viscous particle medium at a uniform speed, coal dust and deionized water were mixed into different water content of coal slurry, and the resistance of the probe rod under pressure in different water content of coal slurry was measured. It is found that when the cohesion of coal slurry is small, the press-in process tends to be stable, and the intrusion resistance shows a linear-slowly increasing-suddenly increasing trend as the depth of pressure increases.

A Double FBGs Temperature Self-Compensating Displacement Sensor and Its Application in Subway Monitoring.

In order to ensure the effective vibration–reduction and vibration–isolation of the steel spring floating plate rail and meet the safe operation requirements of the subway, a Fiber Bragg Grating (FBG) displacement sensor for the deformation monitoring of the subway floating plate is proposed. The sensor adopts double FBGs to realize temperature self-compensation. The elastic ring is used as the elastic conversion structure after the fiber grating is pre-stretched; the two ends are pasted and fixed in the groove in the diameter direction of the ring, which avoids the waveform distortion caused by the full pasting of the fiber grating. The combination of linear bearing and displacement probe rods can increase stability and reduce friction loss so that the sensor has the advantages of high sensitivity and accurate measurement results. The test results and error analysis show that in the range of 0~20 mm, the sensitivity of the sensor is 164.2 pm/mm, the accuracy reaches 0.09% F.S, and the repeatability error and hysteresis error are only 1.86% and 0.99%, respectively. The thermal displacement coupling experiment proves that the sensor has good temperature self-compensation performance. It provides a new technical scheme for the effective monitoring and condition assessment of the built-in steel spring floating plate rail.

Design of Cone Penetration Test Data Relay Transmission by Magnetic Communication

At present, most cone penetration test experiments use cables to transmit data. The cables not only make the exploration operation very complicated, but also hinder the realization of automatic exploration. An excessively long cable can also bring about additional attenuation and noise during the transmission of probe signal. In order to simplify the procedures of exploration operation and to improve the detection accuracy, a cableless cone penetration test system is proposed in this study. It improved the system by using magnetic communication and converts the electrical signal into a magnetic signal at the connection of two adjacent probe rods for relay transmission. Exploratory experiments were carried out to evaluate the feasibility and accuracy of the new system. The experimental results show that the experimental data collected by the new system is more accurate than that collected by traditional CPT equipment with cable. The new system simplifies exploration operations and enables real-time data transmission to detect abnormalities in time. This anomaly usually means that the probe is pressed against hard rock. It is more convenient and accurate to use the new system for exploration.

Development and Application of an Intelligent Plant Protection Monitoring System

Facing the need of modern agriculture to accurately grasp the information of farmland diseases and pests, this paper proposes an intelligent plant protection system. The system is composed of a wireless lens, temperature and humidity sensor, intelligent information terminal, and probe rod to realize the collection of plant images and meteorological information. At the same time, a software based on the mobile terminal and the computer terminal was developed. The plant images and meteorological data are transmitted to the server through Wi-Fi transmission. Combined with the expert knowledge model, a solution is generated, and the user can identify the current diseases and pests and obtain solutions at any time. The system can remotely and automatically monitor and warn of mainstream diseases and pests of field crops such as rice and wheat and provide support for fine plant protection management.

RheoTack—An approach to investigate retraction rate dependent detaching behavior of pressure sensitive adhesives

Characterization methods of pressure sensitive adhesives (PSA) originate from technical bonding and do not cover relevant data for the development and quality assurance of medical applications, where PSA with flexible backing layers are adopted to human skin. In this study, a new method called RheoTack is developed to determine (mechanically and optically) an adhesion and detaching behavior of flexible and transparent PSA based patches. Transdermal therapeutic systems (TTS) consisting of silicone-based PSAs on a flexible and transparent backing layer were tested on a rotational rheometer with an 8 mm plate as a probe rod at retraction speeds of 0.01, 0.1, and 1 mm/s with respect to their adhesion and detaching behavior in terms of force-retraction displacement curves. The curves consist of a compression phase to affirm wetting; a tensile deformation phase intercepting stretching, cavity, and fibril formation; and a failure phase with detaching. Their analysis provides values for stiffness, force, and displacement of the beginning of fibril formation, force and displacement of the beginning of a failure due to fibril breakage and detaching, as well as corresponding activation energies. All these parameters exhibit the pronounced dependency on the retraction speed. The force-retraction displacement curves together with the simultaneous video recordings of the TTS deformation from three different angles (three cameras) provide deeper insight into the deformation processes and allow for interpreting the properties’ characteristics for PSA applications.

Development and application of the 3000 m-level multiparameter CPTu in-situ integrated test system

Accurate knowledge of the mechanical properties of deep-sea sediments and various parameters of the seafloor environment is extremely important for deep-sea geological investigations. In this paper, a set of self-developed 3000 m-level multiparameter CPTu in-situ integrated test system is developed, which successfully solves the technical problems existing in deep-sea CPTu detection technology, hydraulic fine control penetration technology, coaxial cable and optical cable composite transmission technology, etc. A multi-functional integrated probe rod is successfully developed, which contains 3000 m-level CPTu detection technology, single rod 3 D four-way stereo resistivity measurement technology, sediment geochemical environment multiparameter puncture detection technology, and rapid detection of seafloor sediment temperature gradient technology, which can simultaneously obtain in-situ physical and mechanical properties of sediments and various geochemical indicators. It can realize the synchronous operation of static penetration of deep-sea integrated probe rod, static sampling of surface sediment and undersea camera, which breaks the limitation of single parameter and ensures the authenticity and validity of data. At present, the equipment has been successfully sea-tested in the Shenhu Sea Area of the South China Sea and obtained better data feedback, which can provide guidance and technical support for deep-sea mining, gas hydrate mining, deep-sea exploration and other operations.

Standardizing Heat Pulse Probe measurements for thermal property determination using ice and water

The growing demand for Heat Pulse Probes (HPPs) to estimate thermal properties and surrogate soil processes comes with a need for improved standards for calibration and validation in reference materials. This study proposed air-free ice as a calibration material to determine the apparent rod spacing (rc) for HPPs. The advantage of using air-free ice as a calibration standard over agar-stabilized water stems from the fact that at 0 °C ice provides a reference volumetric heat capacity (Cv = 1.93 MJ m−3 °C−1), less than half that of water (Cv = 4.22 MJ m−3 °C−1), while ice provides a four times larger reference thermal conductivity value (λ = 2.16 W m−1 oC−1) relative to that of water (λ = 0.56 W m−1 °C−1), which leads to a sharper peak temperature rise curve that may improve thermal property estimates in ice compared to the elongated peak obtained in water. We performed rc calibrations with air-free ice in a freezer at −21 °C and agar-stabilized water at 21 °C using both Infinite-Line Source (ILS) and Identical-Cylinders Perfect-Conductors (ICPC) models to fit λ and Cv to temperature rise data and compute thermal diffusivity (κ) from the fitted λ and Cv (i.e., κ = λ/Cv). Results showed that the ICPC model yielded similar rc values in both air-free ice and agar-stabilized water with reduced Total Error (TE) in estimating λ, Cv, and κ compared to results with the conventional ILS model. We suggest air-free ice as another standard for Heat Pulse Probe (HPP) rod spacing calibration and sensor-based thermal property validation.

Field observation of the wave-induced pore pressure response in a silty soil seabed

Liquefaction of seabed sediments under the action of storm waves is an important form of seabed instability, which may cause damage to submarine structures such as pipelines and cables. A commonly used parameter to identify sediment liquefaction is pore pressure. The pressure response of the pore water at different depths of a silty soil seabed under storm waves was monitored by a probe rod in the Yellow River delta. The probe is made of a steel pipe with a length of 8 m and an outer diameter of 10 cm, which is equipped with 10 pore pressure sensors. According to the collected data, under a water depth of 8 m, silty soil seabed liquefaction starts when the significant wave height reaches 0.5 m, and the liquefaction depth is between 3.3 and 3.8 m under waves with a significant wave height of 3.65 m. Seabed liquefaction develops in a top-down manner, and the average development rate of the liquefaction depth is approximately 0.17 m/min.

Effectiveness of the Application of Nitrification Inhibitors on the Content of Available Nitrogen Forms in the Soil after Winter Barley Cultivation

Abstract The aim of this study was to examine the effect of split and one-time application of nitrogen-sulphur fertiliser ENSIN (26% N, 13% S) containing nitrification inhibitors (dicyandiamide and 1,2,4-triazole) on the content of nitrate and ammonium nitrogen in soil. The study was conducted in field small-plot experiment with winter barley on Haplic Luvisol with dominance of clay fraction in experimental station of the Central Testing Institute in Agriculture of Veľké Ripňany in the experimental years 2015 to 2017. The dose of nitrogen in all experimental treatments was 140 kg/ha and was applied at once during regenerative fertilisation or split in three partial doses. Soil samples from all examined treatments were taken from two soil depths (0.0‒0.3 m and 0.3‒0.6 m, respectively) by probe rod in three week intervals. Achieved results indicate that in the year 2015/2016, one-time application of fertiliser ENSIN containing nitrification inhibitors considerably reduced portion of N-NO3 - from the content of Nmin by 32 relative % in soil depth of 0.0-0.3 m and by 36 relative % in soil depth of 0.3‒0.6 m. On the other hand, in the year 2016/2017, split application of fertiliser ENSIN substantially reduced portion of N-NO3 - from the content of Nmin by 38‒62 relative % in soil depth of 0.0‒0.3 m, however increased portion of N-NO3 - by 10‒14 relative % in soil depth of 0.3‒0.6 m

Long Period of Time Cooling Technique Using Liquid Nitrogen for HTS-SQUID System

We examined the design method of a glass Dewar for liquid nitrogen as a cooling apparatus of an HTS-SQUID system for field use. Cooling technique without stressing operators is very important. Although cooling technique using liquid nitrogen is suitable to cool HTS-SQUIDs fast at an operation site and operate them without additional noise, the operation time of SQUIDs is often limited by the holding time of liquid nitrogen. To design a system with adequate size and operation time, it is important to estimate the holding time of the cryostat. We calculated the heat inflow due to thermal conduction through the glass Dewar, probe rod, wirings to the SQUID, silver coating on the glass, heat insulator, and nitrogen gas, as well as the heat radiation from the surface of the heat insulator. We compared these results with the measured data for three types of glass Dewar. We successfully develop a simple model to calculate the holding time of the Dewar, and achieved the holding time of more than 100 h for 0.8 L of liquid nitrogen.

Development of Mackintosh Probe Extractor

Dynamic probing is a continuous soil investigation technique, which is one of the simplest soil penetration test. It basically consist of repeatedly driving a metal tipped probe into the ground using a drop weight of fixed mass and travel. Testing was carried out continuously from ground level to the final penetration depth. Once the soil investigation work done, it is difficult to pull out the probe rod from the ground, due to strong soil structure grip against probe cone and prevent the probe rod out from the ground. Thus, in this case, a tool named Extracting Probe was created to assist in the process of retracting the probe rod from the ground. In addition, Extracting Probe also can reduce the time to extract the probe rod from the ground compare with the conventional method. At the same time, it also can reduce manpower cost because only one worker involve to handle this tool compare with conventional method used two or more workers. From experiment that have been done we found that the time difference between conventional tools and extracting probe is significant, average time difference is 155 minutes. In addition the extracting probe can reduce manpower usage, and also labour cost for operating the tool. With all these advantages makes this tool has the potential to be marketed.

Vplyv inhib�torov nitrifik�cie na obsah prijateln�ch foriem p�dneho dus�ka pri pestovan� kukurice siatej (Zea mays, L.)

The objective of this research was to investigate the effect of nitrification inhibitors (dicyandiamide and 1,2,4 triazole) on the content of nitrate and ammonium nitrogen in the soil and the effectiveness of nitrogen-sulphur nutrition of maize. The research was conducted in field small-plot experiment with maize on Haplic Luvisol with dominance of clay fraction in experimental years 2012 to 2015. The dose of nitrogen in all experimental treatments was 160 kg*ha-1 and was applied at one shot or split in three partial doses. Soil samples from all examined treatments were taken from three soil depths (0.0-0.3 m, 0.3-0.6 m and 0.6-0.9 m, respectively) by probe rod in 4- 5 week intervals. Achieved results indicate that on the average of four years and three depths of the soil profile, application of nitrification inhibitors contained in fertilizer ENSIN considerably reduced portion of nitrate nitrogen from the content of mineral nitrogen in the soil by 7-32 relative %. The application of fertilizer ENSIN considerably increased content of ammonium nitrogen in the soil by 10-59 relative %. A favourable effect on increase of ammonium nitrogen content and reduction of nitrate nitrogen content was found out in spite of the fact that in this treatment the total dose of fertilizer was applied at one shot.

Constant energy calibration for permittivity based moisture probes

Summary Soil moisture or soil water content (SWC) is an important variable and its determination with an acceptable accuracy is an essential need for a variety of hydrological disciplines. Among the alternatives, permittivity based probes are gaining popularity and becoming established techniques. However, probes are affected by local soil conditions, requiring soil-specific calibrations for accurate and reliable measurements. Measurement errors associated with these probes can be classified in three groups as primary, secondary and tertiary. Primary errors are mostly associated with the underlying operating principles of a probe. Soil density variation is inherently the major source of secondary error as it can create a measurement error as much as 0.030 m3 m−3. The error associated with the secondary variables can be reduced by up to 0.015 m3 m−3 by targeting the half range of the density variations. Currently available techniques do not explicitly quantify/minimize the secondary errors. Tertiary errors arise mostly from user dependent factors associated with probe-soil contact discontinuities and unexpected small scale environmental variations in the vicinity of the measurement point. This study presents a unique approach in considering the natural variations of the dry density by proposing to conduct the soil specific calibrations on repacked samples under constant compaction/compression energy of 350 kN m/m3. A simple probe insertion procedure was also employed by using guides and predrilling for probe rods in order to minimize the tertiary variables. A comparative assessment of the proposed calibration approach was conducted, considering a time domain reflectometry (TDR) probe and two relatively affordable moisture probes with different operating principles (ThetaProbe ML2x and Wet-2 sensor). The findings of this study showed that accuracy levels of 0.012 m3 m−3, 0.015 m3 m−3 and 0.016 m3 m−3, through Root Mean Square Error (RMSE), were achieved for TDR, ThetaProbe and WET sensor, respectively, for a wide range of soil types including the clays and silts. It is concluded that the proposed constant energy calibration approach help contain the secondary effects due to density variation in a tight range and that the recommended probe installation procedure help minimize the tertiary effects associated with the probe-soil contact discontinuities.