Field Test Results Research Articles

Study on the Diffusion Parameters of Newtonian Fluid in High-Pressure Jet Disturbance Grouting

In order to investigate the diffusion mechanism of slurry in post-pile grouting, this study develops a formula for calculating the diameter and the climb height of the cement core of jet grouting (CCJG). This research conducts field orthogonal tests using a self-developed grouting nozzle to analyze the effects of disturbance pressure (DP), disturbance time (DT), grouting pressure (GP), and the water–cement ratio (W/C) on the dimensions and strength of the CCJG. The findings revealed that the theoretical formula for calculating the diameter of the CCJG deviates by approximately 8% from the field test results, confirming the formula’s validity. In addition, the DP and DT significantly influence the volume of the CCJG, displaying a linear increase with their augmentation. Conversely, the W/C and DP predominantly affect the CCJG’s strength. Notably, an increase in the W/C results in diminished strength, whereas an increase in the DP enhances it. In addition, soil reinforcement is achieved through replacement, mixing, and compaction as the grout flows outward from the center of the grouting hole. These insights offer a theoretical foundation and technical support for effective grouting construction practices.

The pressure drop of fibrous surface filters for gas Filtration: Modeling and experimental studies

Surface filters are extensively utilized for the control of particulate matter and air pollution, and predicting the pressure drop can offer theoretical guidance in the selection of operational parameters for fibrous surface filters. However, there is presently a dearth of efficient and user-friendly methods for predicting the pressure drop. This paper focuses on the accurate and convenient prediction of the pressure drop of fibrous surface filters for gas filtration. Firstly, an analytical model for pressure drop, including the blocked fiber layer and the dust cake, was developed by considering the characteristics of the filter media, dust properties, and loading conditions. The model was validated through laboratory experiments, and the relative error between the model values and experimental data remains within a 15% error. Furthermore, based on the model, the quantitative analysis of the relationship between the pressure drop of the fiber layer and the pressure drop of the dust cake, and the filtration parameter importance were conducted. The influence of filtration parameters on the pressure drop follows the order of filtration velocity, dust concentration, and dust particle size, which provides guidance for choosing the gas filtration operating conditions in the efficient and low-resistance operation of surface filters. Additionally, the model was validated through field test data collected with large-scale cartridge filters in bulk grain loading. The predicted values fit well with the field test results. Overall, this study provides a promising tool for predicting the pressure drop of fibrous surface filters.

Three-dimensional elastoplastic analysis of strain-softening surrounding rock based on the non-linear bond-slip relationship considering hydraulic-mechanical coupling

After the anchor is installed, relative slip between the anchor and the surrounding rock will occur in the actual engineering. Based on the proposed nonlinear bond-slip model, a three-dimensional elastoplastic analysis of the strain-softened surrounding rock is performed in this study while considering hydraulic-mechanical coupling. A numerical iterative method of surrounding rock analysis is proposed, which considers the relative slip between the anchor and the surrounding rock. These stresses and displacements of the surrounding rock, as well as the anchor shear stress distribution, can be obtained using the proposed method. Furthermore, the calculation results of the program are compared with the existing field test results and with the calculation results of other methods to verify the accuracy of the proposed method. The results indicate that the calculation results of the proposed method are generally in line with the test results, and the largest slips occurring at the two ends of the anchors. Meanwhile, the proposed method is applied to an actual engineering, and the results agree well with the field data. Finally, the effects of seepage and strain softening of the surrounding rock on the interaction between the surrounding rock and the anchors are investigated by parametric analysis.

Research on bearing capacity of piles with negative skin friction based on field test

There are extensive deep soft soil layers in the coastal areas of China, and the drainage consolidation method is widely adopted for foundation pretreatment in these areas. However, there are still dozens of centimeters of post construction settlement, which may produce negative skin friction on the pile foundation. To accurately estimate the magnitude of negative skin friction, two prestressed high strength concrete pipe piles with different pile end holding layers were used to conduct field tests. The development law of negative skin friction of pile foundation with soil consolidation is studied by simulating different pre-load height conditions of soil around pile. The monitoring results of field tests indicate that with the soil settlement around the pile, the dragload increases gradually and the neutral point moves downward. When the relative displacement between the pile and soil is 87 cm, the neutral point position of the end bearing pile is approximately 44.6-m deep, and the dragload is about 3640 kN, while the friction pile is 30 m and 2160 kN. The analysis shows that if the pile foundation construction is carried out during the foundation pretreatment, the dragload is considerably large, and this may lead to excessive settlement and damage of the pile.

ANALISIS KINERJA OVER CURRENT RELAY (OCR) & GROUND FAULT RELAY (GFR) PADA PENYULANG 20KV GB5 ULTG GORONTALO MENGGUNAKAN ALAT UJI CMC 356

This research was conducted to test the reliability of the performance of the OCR-GFR relay whether it complies with the settings or not during field testing and to find out a comparative analysis of the performance of theoretical calculations with the results of field testing using the CMC 356 test equipment. This research uses a descriptive method. This research aims to determine whether the performance of the OCR–GFR relay that is being used is still good performance or suitable for use. And the tests carried out are pick up and drop off tests and characteristic tests. The results of the OCR pick-up and drop-off relay test were 1.2 A and the drop-off was 1.134 A. Meanwhile, for the GFR relay the pickup relay was 0.20 A and the drop-off was 185.0 mA. The results of the pickup and drop-off tests can conclude that the relay works according to its settings. Meanwhile, for field testing, the OCR relay characteristics at 1.5 times the setting current are 3.627 s and the theoretical calculation results are 3.697 s. For the GFR relay, the field test results obtained were 1.5 times the setting current, namely 1.981 s, and the theoretical calculation results were 1.977 s. This means that the test results are close to the calculated values. This shows that the Micom P142 OCR/GFR Relay tested is still in good performance.

The role of ZC3H12D-regulated TLR4-NF-κB pathway in LPS-induced pro-inflammatory microglial activation

Lipopolysaccharide (LPS) is an important neurotoxin that can cause inflammatory activation of microglia. ZC3H12D is a novel immunomodulator, which plays a remarkable role in neurological pathologies. It has not been characterized whether ZC3H12D is involved in the regulation of microglial activation. The aim of this study was to investigate the role of ZC3H12D in LPS-induced pro-inflammatory microglial activation and its potential mechanism. To elucidate this, we established animal models of inflammatory injury by intraperitoneal injection of LPS (10 mg/kg). The results of the open-field test showed that LPS caused impaired motor function in mice. Meanwhile, LPS caused pro-inflammatory activation of microglia in the mice cerebral cortex and inhibited the expression of ZC3H12D. We also constructed in vitro inflammatory injury models by treating BV-2 microglia with LPS (0.5 μg/mL). The results showed that down-regulated ZC3H12D expression was associated with LPS-induced pro-inflammatory microglial activation, and further intervention of ZC3H12D expression could inhibited LPS-induced pro-inflammatory activation of microglia. In addition, LPS activated the TLR4-NF-κB signaling pathway, and this process can also be reversed by promoting ZC3H12D expression. At the same time, the addition of resveratrol, a nutrient previously proven to inhibit pro-inflammatory microglial activation, can also reverse this process by increasing the expression of ZC3H12D. Summarized, our data elucidated that ZC3H12D in LPS-induced pro-inflammatory activation of brain microglia via restraining the TLR4-NF-κB pathway. This study may provide a valuable clue for potential therapeutic targets for neuroinflammation-related injuries.

Investigating the Utility of a Compact Loudspeaker Array for Audiometric Testing.

This project addressed the uses of a loudspeaker array for audiometric measurements. It sought to evaluate a prototype compact array in terms of the reliability of test results across sound booths. A seven-loudspeaker array was developed to deliver sounds from -60° to +60° on an arc with a radius of 0.5 m. The system was equipped with a head position sensing system to maintain the listener's head near the optimal test position. Three array systems were distributed to each of the two test sites for within-subject assessments of booth equivalence on tests of sound localization, speech reception in noise, and threshold detection. A total of 36 subjects participated, 18 at each test site. Results showed excellent interbooth consistency on tests of sound localization using speech and noise signals, including conditions in which one or both ears were covered with a muff. Booth consistency was also excellent on sound field threshold measurements for detecting quasi-diffuse noise bands. Nonequivalence was observed in some cases of speech-in-noise tests, particularly with a small one-person booth. Acoustic analyses of in situ loudspeaker responses indicated that some of the nonequivalent comparisons on speech-in-noise tests could be traced to the effects of reflections. Overall, the results demonstrate the utility and reliability of a compact array for the assessment of localization ability, speech reception in noise, and sound field thresholds. However, the results indicate that researchers and clinicians should be aware of the reflection effects that can influence the results of sound field tests in which signal and noise levels from separate loudspeakers are critical.

Through-Ice Acoustic Communication for Ocean Worlds Exploration.

Subsurface exploration of ice-covered planets and moons presents communications challenges because of the need to communicate through kilometers of ice. The objective of this task is to develop the capability to wirelessly communicate through kilometers of ice and thus complement the potentially failure-prone tethers deployed behind an ice-penetrating probe on Ocean Worlds. In this paper, the preliminary work on the development of wireless deep-ice communication is presented and discussed. The communication test and acoustic attenuation measurements in ice have been made by embedding acoustic transceivers in glacial ice at the Matanuska Glacier, Anchorage, Alaska. Field test results show that acoustic communication is viable through ice, demonstrating the transmission of data and image files in the 13-18 kHz band over 100 m. The results suggest that communication over many kilometers of ice thickness could be feasible by employing reduced transmitting frequencies around 1 kHz, though future work is needed to better constrain the likely acoustic attenuation properties through a refrozen borehole.

Automated pixel-level pavement marking detection based on a convolutional transformer

Accurate detection of pavement markings at the pixel level is crucial for enhancing traffic safety. The majority of current advanced deep-learning networks predominantly focus on localized features, neglecting the global context of pavement image. Such networks often result in discontinuous segmentation outcomes and suboptimal recovery of local details. In this paper, a robust model named C-Transformer is proposed to provide an effective solution to this challenge. The contributions of this paper primarily involve two aspects. Firstly, the proposed C-Transformer is designed to succinctly integrate convolution operations and self-attention, facilitating a comprehensive understanding of essential features. Secondly, an efficient Feed-Forward Network called Inverse Residual Feed-Forward Network is also proposed in this paper and deployed in C-Transformer to improve latent representations. Experimental results demonstrate that, compared to other state-of-the-art networks, the proposed C-Transformer achieves a performance enhancement of 0.93% in F-measure and a 1.64% improvement in Intersection-Over-Union. In particular, the robustness and effectiveness of the C-Transformer in accurate pavement marking detection are proved through field test results. This paper illustrates the feasibility of employing a hybrid Convolutional neural network-Transformer-based network for automatic robust pavement marking detection under noisy conditions.

What’s the typical issues influencing operation performance of HVACs in super high-rise buildings? Field tests and optimization analysis

The HVACs in super high-rise buildings commonly consists of variable air volume (VAV) systems, multistage chilled and cooling water systems, primary-secondary chilled water system in chiller plant, and the chillers combination is much more complex, leading to the significantly higher energy consumption than that of normal buildings. This paper contains field tests and comparative studies on the operation performance of HVACs in two super high-rise buildings and summarized representative issues accounting for the high energy consumption. Field test results showed that the annual energy efficiency of the whole HVAC system, before being commissioned, was only 1.79 and 2.15 in two projects. The HVACs, typically VAV systems, chilled and cooling water systems, all suffered from over-supplying and energy wasting. Besides, the chillers commonly operated with a low partial load ratio (PLR), whose energy performance was much lower than expected. Aiming to dig out the typical issues, analyses were carried out from external, internal factors, and their interconnection. Furthermore, optimization methods were put forward with corrected vital indexes. Results showed that proper control strategies should maintain the VAV system, multistage chilled and cooling water system operating with significant distribution temperature differences, tiny distribution pressure drops, and high energy efficiency, thus achieving energy saving and ensuring space cooling effects. Besides, the control strategies, especially the number control of chillers, were influential during the whole cooling season to ensure the chillers operate with optimal PLR and thus achieve better energy performance.

Mechanical testing and numerical simulation of intelligent terminal structure of rockbolt used as a deformable support and for safety monitoring in rock engineering

The nonlinear mechanical behavior perception and deformation control of engineering rock masses are crucial technical challenges in the fields of underground engineering support and safety monitoring. An intelligent terminal structure (ITS) of rockbolts was designed for deformable support systems and safety monitoring in rock engineering applications. It is a type of device installed at the end of a traditional bolt. The ITS comprises two key components: a memory tooth and a yielding ring. This study introduces the design principle of an ITS in deformable rockbolt support systems. It proposes design parameters for the ITS in relation to the deformations encountered by engineering rockbolts. Tests were conducted to measure the ultimate bearing capacity and deformation of the ITS under pull-out conditions. The results demonstrate that the ITS of rockbolt undergoes deformation in the form of elongation as opposed to conventional bolts. Furthermore, finite element numerical simulations were conducted to investigate the mechanism of interaction between the memory tooth and yielding ring of the ITS. The numerical simulation results are consistent with the experimental results. The load capacity of the yielding ring exceeded that of the memory tooth. The field test results indicate that the dilatation of the surrounding rock mass causes ITS deformation in the diversion tunnel. The axial stress load exerted on the rockbolt is transferred to the ITS, leading to memory tooth breakage and compression deformation of the yielding ring. This mechanism allows the load and deformation of the surrounding rock mass to be reflected. The ITS not only serves as a deformable support system but also plays a significant role in monitoring the stress and deformation of the rock mass.

Preparation and fire extinguishing characteristics of inorganic solidified foam with large amount of slag

ABSTRACT Aiming at the problems of conventional cement-based foam plugging and filling materials, such as large amount of cement, low utilization rate of solid waste, unclear bonding, and plugging mechanism, it was proposed that a kind of plugging and preventing fire material named inorganic solidified foam was prepared from industrial slag, cement, and water-based foam as the main raw materials. Based on the fluidity, expansion ratio and mechanical strength of solidified foam, it was determined that S105 slag powder with high content of 60%~65% and the optimal content of the chemical activator 6%. The dry density of solidified foam was about 410~450 kg/m3, and the compressive strength reached 0.5~0.55 MPa. The formation process, the bonding-reinforcement mechanism, and the fire prevention characteristic fire of solidified foam were explored. The results showed that solidified foam could significantly improve the pozzolanic activity of solid waste under the effect of physical and chemical synergy, promoted the hydration reaction of the material, increased the structural compactness of the hydration product of the material, further improving the strength. Fire-fighting experiments and field application exhibited that solidified foam could rapidly diffuse and accumulate to high places through crack channels, quickly extinguish and cool down, and coat loose high-temperature coal piles, showing excellent effect of preventing coal spontaneous combustion. Moreover, the field test results showed that the solidified foam could quickly plug the air leakage, and reduce the CO concentration in the air leakage are. Specifically, the CO concentration of high falling area decreased from 315 ppm to 22 ppm in 3 days, eventually stabilizing below 10 ppm, thereby timely inhibiting the development of spontaneous combustion fire.

Static lateral pile analysis of Dubai sedimentary rock in UAE

Analysis and calculation of lateral pile load capacities using appropriate methods is a challenging task for geotechnical engineers. Primarily, piles in Dubai, UAE, are rock fully socketed with top strata of medium dense to dense silty sand or sedimentary rock resisting lateral loads. In this study, the results of two field pile lateral load tests were chosen for examining different methods used by local geotechnical engineers, where ground lithology constitutes fragile sandstone up to ∼8 m below ground level overlying extremely weak conglomerate/siltstone. Assessing the efficacy of design parameters and analysis methodology is a pivotal aspect in preliminary evaluation of the lateral load capacity of piles. In this research, two commonly adopted approaches (non-linear p–y analysis using the LPile software and finite-element analysis using the Plaxis 3D software) were assessed by comparing them with field test results to predict the lateral load capacity precisely. Design parameters were based on borehole data and laboratory tests near the test location. Even though finite-element analysis predicted better than non-linear p–y analysis, lateral load capacities were underestimated in both piles analysed, which was related to assessment of input parameters. In addition, finite-element analysis was used to back-calculate the elastic modulus of rock that yields lateral deflections of piles close to field test results.

STUDY OF DEFORMABILITY OF THE LARGE-SPAN ROOF STRUCTURAL SYSTEM IN THE FORM OF AN ASYMMETRICAL SHELL

The scientific article is devoted to a complex study of deformability of saddle-type shell of negative Gaussian curvature of a public object that has been in operation for a long time for further general restoration of the building’s roofing system. The authors have developed a specific algorithm for conducting experimental research, providing additional static load on a shell at the lower point of the gentle axial line of the supporting arches. To smoothly carry out the loading procedure, we mounted containers in barrel form on the roof surface and gradually filled them with water. We carried out an experimental evaluation of the bearing capacity of the shell with the determination of the redistribution of forces along the length of the section in the lower zone of the conventionally outlined arch. The experimental test results revealed that the deformability of the shell surface under short-term loading did not exceed 2.0 mm, and, under long-term loading, it was no more than 4.0 mm. Analysis of the qualitative features of structure deformation shows that the displacement of the roof’s points, located symmetrically to the vertical axis, has the opposite sign to the sign of the displacement of the actual ‘saddle’ point (the case of symmetrical deformation). We conducted a numerical verification of the behaviour of the investigated structure by forming a detailed finite element spatial model of the shell. Comparison of the results of numerical calculation with the results of field tests shows the coincidence of qualitative and quantitative parameters, which, in turn, characterises the developed theoretical model as fully adequate and suitable for analysing the stress-strain state of similar large-span structural systems. Based on the results of comprehensive theoretical and experimental research, we made proposals for the further restoration of the roofing structure with the limitation of the self-weight of the covering to 1 kN/m2. Engineers and scientists can use the research results to reconstruct similar authentic structural systems. Keywords: calculation, restoration, loading, deflection, shell, negative Gaussian curvature.

Model predictive control for optimal dispatch of chillers and thermal energy storage tank in airports

Cost of energy consumption is one of the biggest operational cost for airports, and it is increasing from time to time as airports expand to support growing number of passengers. Various factors affect the energy consumption including efficiency of airport Heating Ventilation and Air conditioning (HVAC) systems, which in turn depends on the efficiency of individual subsystems. In this paper, we present an optimal scheduling method for the central plant system at Dallas Fort Worth airport, involving chillers, pumps, and a thermal energy storage (TES) system. A model predictive control (MPC) problem is formulated to minimize both energy and demand charge costs while satisfying the cooling needs of the airport. The proposed Mixed-Integer Nonlinear Programming (MINLP) formulation includes performance curve based models for chillers and pumps and a simplified state of charge model for TES. The formulation also includes predictions of cooling load and chilled water return temperature. Simulation results for a month in summer show savings around 10% compared to the baseline. Initial recommendations based on insights from simulation results to the manual operation procedures resulted in significant savings. Field test results show a 7% chiller efficiency improvement.

Interaction effect of crocin and citalopram on memory and locomotor activity in rats: an insight into BDNF and synaptophysin levels in the hippocampus.

Selective serotonin reuptake inhibitors (SSRIs) are widely used drugs for the treatment of depression. Citalopram is one of the most prescribed SSRIs that is useful for the treatment of depression, obsessive-compulsive disorder, and anxiety disorders. On the other hand, crocin (active constitute of saffron) has pro-cognitive and mood enhancer effects. Also, both citalopram and crocin affect the function and expression of brain-derived neurotrophic factor (BDNF) and synaptophysin, two molecular factors that are involved in cognitive functions and mood. In the present study, we aim to investigate the interaction effect of citalopram and crocin on rats' performance in the open field test (locomotor activity and anxiety-like behavior) and the shuttle box (passive avoidance memory). Citalopram was injected at the doses of 10, 30, and 50mg/kg, and crocin was injected at the dose of 50mg/kg; all administrations were intraperitoneal. Real-time PCR was used to assess the expression level of BDNF and synaptophysin in the hippocampus. The results showed that citalopram (30 and 50mg/kg) impaired passive avoidance memory and decreased BDNF and synaptophysin expression in the hippocampus, while crocin reversed memory impairment, and BDNF and synaptophysin expression in the hippocampus of rats received citalopram 30mg/kg. Also, crocin partially showed these effects in rats that received citalopram 50mg/kg. The results of the open field test were unchanged. In conclusion, we suggested that BDNF and synaptophysin may be involved in the effects of both citalopram and crocin.

Ultra-fast tuning of neural network controllers with application in path tracking of autonomous vehicle

Neural network (NN) controllers have shown great potential in solving complex control or decision-making tasks. However, most of the NN controllers either rely on the availability of large datasets or require dense interactions with the environment, which hinders their application in real systems. In this paper, we introduce a model-based reinforcement learning (MBRL) algorithm, aimed at realizing ultra-fast tuning of deep NN controller from a small sample set of real-world data. The algorithm uses Gaussian processes (GPs) to model the unknown dynamics of real system and updates controller parameters through stochastic gradient descent. By using particle-based method for long-term predictions, the algorithm can easily incorporate online state estimators and filters into controller learning, which is conductive to learning from systems with partially measurable states and stochastic control delay. We apply the algorithm to calibrate a deep NN controller for the path tracking of a full-size autonomous vehicle (AV). Simulation and field test results show that the deep NN controller can be well calibrated after only one interaction with the environment and can achieve similar tracking performance to optimization-based methods such as nonlinear model prediction control (NMPC) in various test scenarios by combining with a feed-forward pure pursuit (PP) controller.

丘陵山地果园单轨式防霜机的仿真与试验

In order to solve the problems of artificial operation, high labor intensity and low efficiency of frost prevention in hilly orchards, this study takes hilly orchards as the research object. Based on the agronomic requirements of frost prevention in hilly orchards, a smoke anti-frost machine based on the transport track of hilly orchards is designed. With the help of Fluent software, the spatial and temporal distribution characteristics of smoke mass concentration and temperature in the process of smoke diffusion are simulated and analyzed based on the discrete phase model. The results show that the smoke continues to erupt at a speed of 6 m / s, and the plume volume gradually increases. After 9 s, the smoke reaches a stable diffusion state. Based on the established smoke diffusion simulation model, the orthogonal test analysis of the working parameters at the smoke outlet of the frost-proof machine was carried out with the temperature increase near the canopy of the fruit tree as the index. The results showed that the best combination of working parameters at the smoke outlet of the frost-proof machine was the smoke outlet speed of 10 m / s, the smoke outlet angle of 60 °, and the smoke outlet diameter of 140 mm. The field test results show that the frost-proof machine can continuously operate for 0.5 h at a running speed of 0.6 m / s, and the temperature in the height range of 1.5 m to 4 m in the working area can be increased by about 1.7 ° C. This study is of great significance to reduce the frost disaster loss of hilly orchards and improve the economic benefits of hilly orchards.

Динамический метод определения несущей способности фундамента, изготовленного в вытрамбованном котловане

The purpose of the study is to develop a dynamic method for determining the bearing capacity of a foundation made in a rammed pit. The research program includes two stages. At the first stage, the pits were made by ramming and measuring «failures» when dumping the ramming. At the second stage, experiments were carried out to study the operation of the foundation when applying a vertical load. According to the results of field tests, it was found that there is a dependence between the values of «failures» when installing a rammed pit and the bearing capacity of the foundation. According to the research results, an engineering method for determining the bearing capacity of a foundation made in a rammed pit is recommended.

Pre- and post-failure behaviour of a dike after rapid drawdown of river level based on material point method

The rapid drawdown of river level is very detrimental to the stability of dikes. In this paper, the entire slope failure process of a real dike with sandy soil interlayer after rapid river drawdown is accurately reproduced using the material point method (MPM). The analysis of pre-failure behaviour, in combination with field test results, reveals the triggering mechanism of such dike slope failure, demonstrating that the presence of sandy soil interlayer is the leading cause of dike instability. By tracking the response of the dike slope from failure initiation to runout termination, the failure mode of the dike slope with sandy soil interlayer is identified as a progressive and retrogressive failure mode, with shallow and deep-seated slip surfaces appearing successively. Parametric studies indicate the friction angle, cohesion, dilatancy, and permeability of the sandy soil play significant roles in dike slope stability. A relationship between the permeability of sandy soil and the maximum sliding displacement is also found. In the face of rapid river drawdown, river-facing slope surface protection is the most effective protection measure for such dike slopes with sandy soil interlayer, while traditional riprap protection at the slope toe has a limited protecting effect.