Field Test Results Research Articles

Rancang Bangun Prototype Sistem Monitoring Suhu, Kelembaban dan Intensitas Cahaya pada Tanaman Cabai Berbasis IoT

Monitoring is a very important activiti y carried out in chili cultivation. A monitoring system on chili plants designed in the form of the Internet of Things (IoT) is an electronic device that can interact directly with users who use it for monitoring and controlling devices with the help of the internet. The creation of the chili plant monitoring based on the Internet of Things (IoT) can facilitate monitoring activities on chili plants to monitor temperature, humidity and light intensity in real time without having to come to the location of chili planters. This study uses quantitative descriptive research by describing the design of a prototype monitoring system for temperature, humidity and light intensity on chili plants based on IoT and describing the results of measuring temperature, humidity and light intensity on the prototype that has been made by researchers. The results of this prototype design have the main components, namely NodeMCU ESP8266, DHT 22 Sensor and BH1750 Sensor. The results obtained for measuring temperature, humidity and light intensity in this prototype show that the R square value on the DHT sensor for temperature and humidity is 0.949 and 0.870 while for the BH1750 sensor value for light intensity is 0.998. The R square value of the sensor is in the interval 0.80-1.00. The results of the calibration measurement carried out on this prototype are considered very valid. Field test results show the sensors and outputs obtained can function very well.

A model-based method of tire-road friction estimation for articulated steering vehicles

Articulated steering vehicles (ASV) are widely used in many industries for their high efficiency and excellent maneuverability. The autonomous driving and intelligent control of ASV are extremely critical owing to the operation characteristics. As a very important parameter, the tire-road friction coefficient (TRFC) determines the extreme tire force directly in the process of intelligent control. However, it cannot be obtained with the existing methods for the harsh environment and special structure of ASV. This paper proposed a two-layer model-based method of tire-road friction coefficient estimation for ASV. The dynamic models of ASV in the XY plane, including the longitudinal and lateral models of frames, tire forces, and steering system models, are established first. The dynamic models are embedded into the upper layer with a Kalman filter (KF) to estimate the tire forces in longitudinal and lateral directions. During the process, some self-contained sensors, including the state sensors of frames and steering system, are used to provide the observation data. In the lower layer, a recursive least square (RLS) method with a forgetting factor is used to obtain the TRFC and tire stiffness parameters with the aid of the tire model. The simulation and field test are carried out to validate the method under comprehensive conditions, in which different steering commands, velocities, and roads are included. The simulation and field test results show that the forgetting factor has a significant influence on the convergence and robustness of the proposed method. The forgetting factor τ = 0.95 is used in the field test, the estimation result of dry concrete road friction coefficient is around 0.83. The results indicated that the proposed method can obtain the TRFC and tire parameters dynamically for ASVs.

Методика оценки несущей способности баретты глубокого котлована в сложных инженерно-геологических условиях г. Ханой

Introduction. At present, the rate of growth in the development of urbanisation processes in large cities is increasing rapidly every year. At the stage of preliminary design of pile foundations, an important part is to determine the bearing capacity of the pile. Barrettes are effective foundation structures, also for high-rise buildings on soft soils. In such conditions, long barrettes are designed. At the same time the used normative methods used of calculating the bearing capacity and settlement do not take into account the features of the stress-strain state of the foundation and the interaction with barrettes in the foundations of high-rise buildings with a developed underground part. Materials and methods. The task has been considered on the basis of the results of field testing with piles (static load method) with the calculation by the analytical method according to the strength characteristics of the soil foundation, described in the regulatory documents SP 24.13330.2011 “Pile Foundations”. A new calculation method is proposed, which is set out in Appendix D of the specified set o.rules, taking into account relevant factors, such as the relative position of piles in the ground, their length, pitch, etc. Results. A graph of the dependence of settlement on load was obtained based on the results of full-scale tests of barrettes with a limiting settlement of 40 mm. Analytical results are compared with field testing of a pile in difficult engineering and geological conditions in Hanoi, Vietnam. Conclusions. The conclusions obtained by the analytical method of calculating the bearing capacity of a single barrette in terms of strength characteristics, taking into account unloading on soft soils during the development of a deep pit, are quite close to the results of static field tests. These solutions can be applied to determine the bearing capacity of piles and barrettes on soft soils.

Practical back-analysis methodology to predict underground train-induced building vibrations.

The vehicle-track interaction leads to the vibrating source for the prediction of train-induced building vibrations. To prevent modeling difficulties in the source part, this study proposes a practical back-analysis methodology for calculating underground train-induced building vibrations. The methodology combines the advantages of field measurements and numerical simulations. The fundamental concept of the hybrid methodology is to first create a virtualized moving source at the rail surface and subsequently modify it until the numerical predictions are consistent with the field measurements at the same locations. These locations are frequently selected at the ground surface or near the building foundation. Finally, this imaginary force can be used to predict the vibrations of buildings. The practicality of the hybrid methodology is verified by comparing the predicted vibrations of buildings with field test results. As an application of the proposed method, the transmission laws and characteristics of the vibrations in buildings are analyzed.

Assessment of arresting performance of foamed concrete arrestors via the coupled discrete element and virtual prototype simulations

Engineered material arresting system (EMAS) is a foamed concrete arrestor that can arrest aircraft overrunning the runway. Identification of the arresting effect of foamed concrete materials on overrunning aircraft is crucial for optimizing EMAS. By coupling the Discrete Element Method (DEM) and the Virtual Prototype Method (VPM), the EMAS crushing process and the aircraft dynamics are simulated simultaneously. The material properties of different foamed concrete were firstly determined via experiments, and then adopted as input for DEM of EMAS. Subsequently, the VPM of A320 aircraft with various overrun speeds was established. The rationality of the DEM-VPM model was verified by the field test result. The sensitivity analysis on the arresting processes reveals that a 67% increase in EMAS thickness and a 102% increase in material strength can enhance the arresting performance by 96% and 11.5%, respectively. However, freeze–thaw has negative effect. In addition, higher overrun speeds of the aircraft can cause greater acceleration and drag forces, and thereby magnify the risk of damage to the aircraft.

Stress Relief and Permeability Enhancement with Hydraulic Fracturing in Overlying Key Strata of Deep and Soft Coal Seams.

The technical problems of high in situ stress, high gas pressure, high gas content, and low coal seam permeability are widespread in deep soft coal seam excavation, which leads to frequent occurrences of dynamic phenomena, such as coal cannons and blowout holes. Based on the high-pressure hydraulic fracturing technology and process, this study puts forward a new technology of gas drainage in deep and soft coal seams by fracturing the overlying key strata to cut off the stress transmission path among coal and rock strata. According to the theories of key layer and masonry beams, the distribution locations of the main and subkey strata are determined, and based on uniaxial compression and Brazilian splitting experiments, the mechanical parameters of key stratum were tested. Combined with the results of numerical simulation and field test, initial pressure and fracturing radius of hydraulic fracturing technology for overlying key strata were determined, the stress relief effect and permeability variation law of coal seam after hydraulic fracturing in the main and subkey strata were analyzed, and then technical schemes for simultaneous fracturing of the key layer were designed. Field application results showed that the stress concentration phenomenon in soft coal seam excavation had been alleviated, and the stress relief effect of coal seam and the permeability were increased obviously. The volume and concentration of gas drainage were increased by 10 and 11%, respectively, the gas amount by 1.22 times; the frequency of dynamic phenomena such as coal cannons decreased by 95%, the gas concentration in return air flow by 20% during mining processes. This paper provided an innovative technical idea and process for gas control in deep and soft coal seam excavation, which could effectively solve the common and difficult problems about frequent occurrences of excessive gas concentration and dynamic phenomena.

Gas Hydrates: Applications and Advantages

Gas hydrates are promising components for a wide range of industries and the national economy. This paper outlines the gas hydrate application areas with the greatest potential. Gas hydrates of methane, ethane, propane, carbon dioxide and freon were investigated. Double gas hydrates were found to be coming into use. Natural and artificial hydrates are now being exploited. The main properties and component composition of hydrates, as well as their extraction methods are described. The key aspects of using hydrates in the energy industry, gas chemistry and petrochemistry, heat exchange systems and fire safety management are highlighted. These specific aspects were identified by analyzing the known experimental findings, results of mathematical modeling, bench and field tests, as well as trial runs of industrial systems. The recent advances in science and technology in this field were analyzed. The range of tasks that need to be tackled to improve the efficiency of using gas hydrates are defined.

INFLUENCE ANALYSIS OF THE DIFFERENT TYPES BUS BODY COMPOSITION ON THE CHARACTERISTICS OF THE AIR FLOWS FORMATION IN CONDITIONS OF FORCED CABIN CONVECTION

The paper proposes the influence analysis of five types of city bus body layouts on the air flows formation in the cabin, generated by the motor compartment fan under conditions of forced convection. The authors conducted three types of tests with different boundary conditions in the finite element calculation module of ANSYS Fluent: the input velocity of the flows from the motor compartment fan, the temperature of the flows and the environment, internal and external convection. According to the results of simulated field tests, it was established that the most effective is the layout of the bus with the engine located horizontally in the rear overhang. Such a layout is relatively expensive from the point of view of production, because it requires the installation of the opposite type of "boxer" engine in most cases, which is characterized by a higher cost, complexity of maintenance and is less common in contrast to V-type internal combustion engine schemes. However, air circulation occurs throughout the cabin the most effectively in this layout scheme, taking into account the driver's cabin and other locations. Layouts with central positioning of the engine (vertical and horizontal) also deserve attention - they ensure a symmetrical distribution of air in the front and rear of the bus body, which can be especially relevant in the cold period of the year.

Backstepping sliding mode control for an active hydraulically interconnected suspension

This paper presents a backstepping sliding mode control (BSMC) method for an active anti-roll hydraulically interconnected suspension (HIS) system. The proposed control strategy enables the active HIS system tracking desired anti-roll moment within the working area. Based on the tracking error, the BSMC controller calculates the flowrate of the control cylinder. This flowrate successively changes the pressure in the accumulators and cylinder chambers, and finally determines the output anti-roll moment of the HIS. The HIS system parameters uncertainty and the system’s nonlinear characteristic are both considered in the proposed BSMC controller. To comprehensively design and validate the proposed control method, a 4-DOF half car model and a corresponding nonlinear active anti-roll HIS model are firstly established. Next, a linear quadratic regulator (LQR) upper layer controller is designed to optimize the vehicle’s roll motion, and the result of the LQR controller is set as a tracking target. Thereafter, the proposed BSMC bottom layer controller is designed to track the target moment. Finally, numerical simulation and experiments on the test bench are conducted to validate the proposed control method. The simulation and bench test results indicate that the proposed active HIS performs well in tracking target and tolerating disturbance. The proposed active HIS expands about additional ±1000 N/m dynamic anti-roll moment compared to a passive HIS at each roll angle, and the response time is less than 70 ms. The field test results show that the active HIS with proposed control method improves anti-roll property compared with a passive HIS by 23.3% in the double lane change test.

Optimization of artificial neutral networks architecture for predicting compression parameters using piezocone penetration test

Soil compression parameters are significant factors for determining settlement to ensure safety of the civil engineering structures. These parameters are strictly evaluated through laboratory tests using samples collected from drilling boreholes. Currently, the testing procedures require both time and labour, and extensively increased construction’s cost in some cases such as in offshore structures. Therefore, it is necessary to establish a robust and reliable method, which can easily be used to obtain these parameters. In this paper, we employ Machine Learning (ML) models to relate field-testing results of piezocone penetration test (CPTu) to the compression parameters. A large database for this study is considered from five different construction projects, including two roads, a factory, and two massive container ports. Based on the database, a sensitivity analysis of the dataset and a feature analysis are performed. Furthermore, in order to select an appropriate ML method, several models are employed such as artificial neural network (ANN), deep neural network (DNN), DNN optimized with genetic algorithms (GA), and DNN optimized with particle swarm optimization (PSO). Comparisons between these ML models are also performed with remarkable better performances from the optimized DNN models than the classical models of ANN or DNN. Finally, validations are carried out using data from Nguyen Son (NS) road project to confirm the effectiveness and reveal the promising potential applications of the proposed methods.

The Anti-Snow Behaviour of Icephobic Coatings: Laboratory and In-Field Testing

Overhead power line conductors and ground wires are affected by ice and snow accretion which can easily adhere to their surface, causing the breakage of cables and the collapse of pylons due to excessive weight. In Italy, the main concern is about wet snow: this phenomenon occurs close to zero degrees Celsius with snow density reaching up to 350 Kg/m3. Anti-icing and anti-snow coatings represent a possible strategy to mitigate ice accretion on overhead power line structures. Many works are oriented to achieve anti-icing properties, starting from superhydrophobic coatings or slippery coatings; however, there is a lack of knowledge about the anti-snow behaviour of these surfaces. In this work, aluminium alloy conductor and ground-wire samples were prepared with different coatings, which include hydrophobic, superhydrophobic and slippery surfaces prepared in the laboratory. Characterisations of sample wettability at room and low temperatures and ice adhesion strength were carried out in the laboratory. Anti-snow behaviour was studied in outdoor test facilities in the Italian Alps during several snowfall events. Furthermore, the environmental parameters were also recorded. Two figures of merit were developed to quantify anti-snow behaviour of the samples: one describing the fraction of surfaces covered by snow during the snowfall event and the other representing the maximum accretion load reached on the samples. Results of laboratory and field testing are compared and discussed. Field testing evidenced a promising snowphobic behaviour for all the samples, despite the different anti-icing and wettability properties measured in the laboratory. The mitigation of the phenomenon was found to occur mainly with two different mechanisms: the delay in snow accretion on the surface and/or the early shedding of the snow-sleeve.

EXPERIMENTAL EVALUATION OF 100 MM CHARGE FOR EXPLOSIVELY FORMED PROJECTILE

The construction of 100 mm charge for explosively formed projectile was proposed in the article. The construction of charge was tested on the range. The results of field tests of an explosively formed projectile with the expected design parameters are presented. The accuracy of projectiles hitting the target at 750 calibre distance was determined. The penetration of projectiles was shown on the examples of impact on a 30 mm thick target from rolled homogenous steel. Exemplary shapes of explosively formed projectiles on the flight path in the form of imprints in a paper target are presented. The results of fragmentation of the charge casing were also analysed.

Research on fault diagnosis system for belt conveyor based on internet of things and the LightGBM model.

As an equipment failure that often occurs in coal production and transportation, belt conveyor failure usually requires many human and material resources to be identified and diagnosed. Therefore, it is urgent to improve the efficiency of fault identification, and this paper combines the internet of things (IoT) platform and the Light Gradient Boosting Machine (LGBM) model to establish a fault diagnosis system for the belt conveyor. Firstly, selecting and installing sensors for the belt conveyor to collect the running data. Secondly, connecting the sensor and the Aprus adapter and configuring the script language on the client side of the IoT platform. This step enables the collected data to be uploaded to the client side of the IoT platform, where the data can be counted and visualized. Finally, the LGBM model is built to diagnose the conveyor faults, and the evaluation index and K-fold cross-validation prove the model's effectiveness. In addition, after the system was established and debugged, it was applied in practical mine engineering for three months. The field test results show: (1) The client of the IoT can well receive the data uploaded by the sensor and present the data in the form of a graph. (2) The LGBM model has a high accuracy. In the test, the model accurately detected faults, including belt deviation, belt slipping, and belt tearing, which happened twice, two times, one time and one time, respectively, as well as timely gaving warnings to the client and effectively avoiding subsequent accidents. This application shows that the fault diagnosis system of belt conveyors can accurately diagnose and identify belt conveyor failure in the coal production process and improve the intelligent management of coal mines.

Study on Bearing Capacity of Reinforced Composite Pipe Pile Group in Reclaimed Stratum under Vertical Load

A new stiffened composite pipe pile was developed for improving the foundation of reclaimed ground in ocean engineering. To study the bearing capacity of the stiffened composite pipe pile group, a combination of field test and finite element method was used. Firstly, field tests were performed on the proposed single stiffened composite pipe pile. The single stiffened composite pipe pile model was verified by comparing the numerical simulation results with the field test results. The load transfer mechanism from the stiffened core to the cemented soil and the surrounding soil was clarified. Further, a 3D finite element model of the stiffened composite pipe pile group was established based on the single stiffened composite pipe pile model. Finally, the bearing capacity of the pile group and the stress distribution of each pile were analysed and the influence of the pile spacing on the pile bearing capacity was discussed. The results showed that the axial stress of both the side and corner piles decreased rapidly with an increase in the pile spacing, and the stress-bearing ratio decreased. The stress-bearing ratio of the central pile increases with an increase in pile spacing. The smaller the pile spacing, the larger the load proportion of the composite pile group and the larger the foundation settlement. The optimal design scheme was a composite pile with a 500 mm stiffened core diameter, 700 mm outer cemented soil diameter, and a spacing between piles of four times the cemented soil diameter (2.8 m) considering the group pile bearing capacity and the economic benefits of the project. These results provide a reference for the design and construction of stiffened composite piles for ground improvement projects.

Infrared detector module for airborne hyperspectral LiDAR: design and demonstration.

Realizing the integrated acquisition and identification of the elevation information and spectral information of the observation target is at the frontier and a future trend of Earth observation technology. This study designs and develops a set of airborne hyperspectral imaging lidar optical receiving systems and investigates the detection of the infrared band echo signal of the lidar system. A set of avalanche photodiode (APD) detectors is independently designed to detect the weak echo signal of 800-900nm band. The actual radius of the photosensitive surface of the APD detector is 0.25mm. We design and demonstrate the optical focusing system of the APD detector in the laboratory and obtain that the image plane size of the optical fiber end faces of the APD detector from channel 47 to channel 56 is close to 0.3mm. Results show that the optical focusing system of the self-designed APD detector is reliable. On the basis of the focal plane splitting technology of the fiber array, we couple the echo signal of 800-900nm band to the corresponding APD detector through the fiber array and conduct a series of test experiments for the APD detector. Field test results of the ground-based platform show that the APD detectors in all channels can complete the remote sensing measurement of 500m. The development of this APD detector solves the problem of hyperspectral imaging under weak light signals and realizes the accurate detection of ground targets in the infrared band by airborne hyperspectral imaging lidar.

Experimental Study of Envelope Airtightness in New Egyptian Residential Dwellings

In residential buildings, air infiltration impacts energy, indoor air quality, and thermal comfort considerably. While air infiltration in residential buildings has been the focus of many studies, most published field-testing results pertain to developed countries, with little or no data on air infiltration in developing nations. This paper presents the results of one of the first field investigations into envelope infiltration in the residential buildings of the hot-arid climatic area of Egypt. To analyze the air permeability of the building envelope, the fan pressurization method, often known as the blower door test (BDT), is used, following ISO 9772. The study focuses on 20 residential dwellings built with heavy construction materials and subjects them to extensive characterization and testing. The average air leakage and the air permeability rate for the tested sample were 6.14 h−1 and 17.3 m3/(h∙m2), respectively. However, significant variations in airtightness were observed across the dwelling, leading the team to test several building-related parameters statistically to study their impact on airtightness. Fenestration quality appeared to be a critical factor in determining air infiltration, showing a strong correlation with the air change and leakage. A further investigation underscored that the specific aperture factor and the fenestration quality can predict the infiltration rates to a large degree. Thus, we recommend further investigation of these characteristics in heavy construction material building. Finally, we strongly recommend that building codes in developing countries such as Egypt include minimum performance requirements for fenestration.

Crack closure effect during the impact coal seam with high-pressure air blasting and the influence of gas drainage efficiency

The crack closure in impact coal seams induced by high-pressure air blasting greatly affects gas drainage efficiency. The length of the crack closure was calculated and analyzed based on energy and elastic theories. The closure region was then determined to be 3.8 m from the blasting hole. The results of a high-pressure air blasting experiment in the underground of one coal mine in China showed that the effect of crack closure on gas drainage efficiency manifested as a decreased amplitude of gas emission in the crack closure region. At 1.0–4.0 m from the blasting hole, the amplitude of gas emission in the observation holes first increased and then decreased with increasing distance from the blasting hole. At 1.8–2.5 m from the blasting hole, the amplitude of the gas emission was maximal. At 4.0 m from the blasting hole, the crack was nearly closed, and the gas emission in the observation holes was minimal. The theoretical calculation had good consistency with the field test results; thus, it can provide an important reference for an appropriate arrangement of gas drainage boreholes.

Green Tea Catechin EGCG Ameliorates Thioacetamide-Induced Hepatic Encephalopathy in Rats via Modulation of the Microbiota-Gut-Liver Axis.

Existing research suggests that (-)-epigallocatechin-3-gallate (EGCG), which is a natural tea catechin active substance, can protect against liver injury. However, its mechanism for hepatic encephalopathy (HE) treatment is still unclear. In this study, the role of EGCG in the amelioration of HE rats and the effect on the microbiota-gut-liver axis are mainly analyzed. Thioacetamide (TAA) is employed to induce the HE model in rats. The results of open field test show that EGCG restores locomotor activity and exploratory behavior. Histological and biochemical results demonstrate that EGCG ameliorates brain and liver damage, decreases the expression of pro-inflammatory cytokines, and increases the activity of antioxidant enzymes. Meanwhile, EGCG modulates the Nrf2 pathway and TLR4/NF-κB pathway to mitigate TAA-induced oxidative stress and inflammatory responses. Immunohistochemistry reveals protection of the intestinal barrier by EGCG upregulating the expression of occludin and zonula occludens-1. Furthermore, serum levels of ammonia and LPS are reduced. 16S rRNA analysis shows that EGCG treatment increases the abundance of beneficial bacteria (e.g., Bifidobacterium, Lactobacillus, and Limosilactobacillus). The above results reveal that EGCG has anti-oxidative stress and anti-inflammatory effects, and ameliorates the condition through the microbiota-gut-liver axis, with potential for the treatment of HE.

Installation Effects and Behavior of a Driven Prestressed High-Strength Concrete Nodular Pile in Deep Saturated Soft Clay

This paper investigated the installation effects of a driven prestressed high-strength concrete (PHC) nodular pile in deep soft clay through full-scale tests, and the behavior of a driven PHC nodular pile is analyzed based on the field test results. The test results demonstrated that the driven PHC nodular pile installation process induced significant disturbance in the surrounding soil. The excess pore water pressures (Δu) that were induced by the installation of a driven PHC nodular pile were larger than the Δu that were induced by the installation of a driven PHC pipe pile. The driven PHC nodular pile installation caused significant Δu in the soil down to 2 m below the pile base, and the Δu became much smaller in the soil at 4 m below the pile base. The Δu dissipated slowly in the soft clay layers, and the Δu in the surficial soil layers dissipated faster than that in the deep soil layers. The nodules along the PHC nodular pile shaft could increase the pile shaft capacity. The measured shaft resistances of 350(400)-mm PHC nodular piles were 1.17–1.18 times the calculated shaft resistances of 350-mm PHC pipe piles in soft clay layers.

Numerical investigations on dynamic responses of subway segmental tunnel lining structures under internal blasts

Numerical simulation of segmental lining tunnel subjected to internal explosive loading is carried out in this paper based on the arbitrary-Lagrangian-Eulerian (ALE) and finite element (FE) coupled algorithms. A high-fidelity FE model considering assembled features of segmental lining structure is established, and the mapping technique is adopted to accurately simulate the explosion process. The calculated overpressure histories and failure modes of the lining structure fit well with field test results of full-scale specimens, indicating the applicability and accuracy of the numerical model. A more comprehensive numerical model considered the practical service state of segmental lining tunnel is further built based on the verified model. Influences of mechanical properties and pressure levels of surrounding soils on dynamic responses of tunnel structure under internal explosion are investigated. Numerical results show that dominated deformation modes of the segmental lining tunnel under the action of internal explosion include opening deformation at the segmental joints of the charged ring and shear deformation between the adjacent rings. The modest explosion caused by terrorist bombing attacks may severely harm the shield tunnel structure and impair its service performance, especially if the tunnel is buried in soft soil at a shallow depth