Actual Process Research Articles

Application of Halogen-Free EPDM Flame Retardants

Flame retardant materials have been widely used in different fields because of their unique physical and chemical properties, such as aerospace and chemical products. However, although the traditional halogen-based flame retardant has shown excellent application performance in the actual application process, there are serious environmental pollution problems after its use. In order to solve the environmental problems caused by halogen flame retardants, different types of environmentally friendly flame retardant materials have been developed, such as ethylene propylene diene monomer (EPDM) flame retardant. As a new type of energy saving and environment friendly rubber, the EPDM has excellent heat resistance, aging resistance, corrosion resistance and insulation performance, and thus it has been widely used in all walks of life. To this end, EPDM has been used to develop different types of flame retardant materials. Herein, this research will mainly analyze the application performance of different types of EPDM flame retardants and their flame retardant mechanisms, where the research and application of EDPM flame retarder are mainly described from three aspects: intumescent flame retarder, phosphorous flame retarder and inorganic flame retarder

An Innovative Approach to Organizational Changes for Sustainable Processes: A Case Study on Waste Minimization

It is necessary to adapt constantly to the business environment with its changing demands. Understanding the objectives, scope, and limitations of actual process changes is crucial, and can be achieved with numerous measures, methods, and techniques. This research demonstrates an innovative approach to organizational changes to enable sustainable processes. In the first part of this research, relevant measures, methods, and techniques are selected through an in-depth literature review. Then, an international online questionnaire is executed among 213 enterprises from four countries. In the last part of this research, the developed approach is tested for the example of waste minimization in the process of developing coatings. Based on the analysis of the survey questionnaire, the usability and benefits of various measures are demonstrated, namely from the point of view of their positive impact on structural and operational efficiency indicators. At the end of the article, a case study presents the success of the innovative approach in terms of 88% waste minimization and up to 48% time and cost reductions in the process of developing coatings. The proposed approach enables better choices to be made and the more efficient use of various measures, which can lead to more sustainable processes and improve the efficiency of enterprises.

Research on leakage environmental risk assessment and risk prevention and control measures in the long-term landfill process of ultra-alkaline fly ash

In this study, we simulated the actual landfill disposal process using accelerated carbonization experiments, based on the leaching characteristics of heavy metals from “alkaline” fly ash, and used the LandSim–HELP coupling model to assess the environmental risk of the leaching. The results showed that the leaching data of “alkaline” fly ash before carbonization showed the illusion of admission to landfill with only a small amount of chemical addition or even without curing/stabilization. The leached concentrations of Zn and Cd from “alkaline” fly ash after carbonation were significantly higher. The risk assessment of the leakage of heavy metals in the case of a single artificial composite liner system showed that the exposure concentrations of Pb, Zn, and Cd in samples exceeded Standard for groundwater quality (GB/T 14848–2017) the Class III permissible limits after carbonation; exposure risk for Cd was exceeded in all samples. However, although the use of a double-layer artificial composite liner to improve the level of impermeability effectively reduced the risk of Cd leaching, so that none of the non-carcinogenic risks exceeded the standard, the carcinogenic risk of Cd in the carbonized samples exceeded the factor of 1.1–4.5 of the acceptable hazard quotient, and the contamination characteristics of the alkaline fly ash still need to be kept in view.

Application of a Core-Shell Structure Nano Filtration Control Additive in Salt-Resistant Clay-Free Water-Based Drilling Fluid

When drilling into a reservoir, the drilling fluid containing bentonite is prone to solid phase invasion, causing serious damage to the reservoir, and the conventional API barite suspension stability is poor, which makes it easy to cause sedimentation and blockage. Therefore, in order to avoid accidents, we use ultrafine barite to obtain a good suspension stability. More importantly, the method of modifying zwitterionic polymers on the surface of nano-silica is used to develop a temperature-resistant and salt-resistant fluid loss reducer FATG with a core-shell structure, and it is applied to ultra-fine clay-free water-based drilling fluid (WBDF). The results show that the filtration loss of clay-free drilling fluid containing FATG can be reduced to 8.2 mL, and AV can be reduced to 22 mPa·s. Although the viscosity is reduced, FATG can reduce the filter loss by forming a dense mud cake. The clay-free drilling fluid system obtained by further adding sepiolite can reduce the filtration loss to 3.8 mL. After aging at 220 °C for 15 d, it still has significant salt tolerance, the filtration loss is only 9 mL, the viscosity does not change much, a thinner and denser mud cake is formed, and the viscosity coefficient of the mud cake is smaller. The linear expansion test and permeability recovery evaluation were carried out. The hydration expansion inhibition rate of bentonite can reach 72.5%, and the permeability recovery rate can reach 77.9%, which can meet the long-term drilling fluid circulation work in the actual drilling process. This study can provide guidance for technical research in related fields such as reservoir protection.

Influence of Some Key Parameters on the Efficiency of Flocculation–Solidification–Filter Press Combined Method for Sustainable Treatment of Waste Mud Slurry

The flocculation–solidification–filter-press combined method is a new type of method for treating waste slurry that combines flocculation and chemical curing with a mechanical filter press. Among these processes, the mechanical filter-press process is key to the efficient disposal of waste engineering slurries by the flocculation–solidification–filter-press combined method. In the mechanical filter-press process, parameters including the initial thickness of filtration mud, the magnitude of filtration pressure, and the duration of press filtration have important impacts on the dewatering and strength after subsequent curing. In this work, a series of laboratory tests were conducted to study the influence of filter-press parameters on flocculated–solidified mud by measuring the properties of treated and cured mud. The test results showed that the initial mud bag thickness is an important factor in the mud treatment effect. As the initial mud bag thickness increases, the greater the water content of the mud at the end of the filter-press process after applying the same amount of time and the same amount of pressure, the lower the post-conservation strength will be. The increase in filtration pressure and filtration time within a certain range can reduce the water content of the mud brick after filtration and significantly improve its shear strength. In the actual process of filtering in the project, the thickness of the initial mud bag should be no more than 140 mm, the filtration pressure is about 0.35 MPa, and the filtration time is suitable for 2 min.

Progressive Dam-Failure Assessment by Smooth Particle Hydrodynamics (SPH) Method

The dam-break water flow is a complex fluid motion, showing strong nonlinearity and stochasticity. In order to better study the characteristics of the dam burst flood, the smooth particle hydrodynamics (SPH) method was chosen to establish a two-dimensional classical dam-burst model, and the flow velocity distribution graph was obtained by calculation and compared with the experimental results in the literature, and the fitting degree of the two was obtained to be 88.4%, which verifies the validity of the model. On this basis, according to the principle of dam failure, the two failure modes of equal-interval gradual failure and progressive gradual failure were simulated, and the water body characteristics such as water flow velocity, energy, pressure, etc., were analyzed based on the different working conditions of the two modes to obtain the characteristics of gradual dam-failure water flow under the two kinds of numerical models. The simulation results show that, compared with the instantaneous dam failure mode, (1) the flow rate of the dam-failure stream reaching the downstream slows down in the gradual dam-failure mode; (2) the depth development of the breach extends downward in layers and stages over time, and the overall duration of the breach is prolonged; (3) the destructive power of the dam-failure flood is weakened as the number of segments increases. The results of the study show that, compared with the instant dam-failure mode, the calculation results of the breach development considering the progressive gradual dam-failure mode are more in line with the theoretical solution and closer to the actual process of dam failure, which can provide ideas and references for advancing the numerical study of dam failure.

Particle Size Effect of Cyetpyrafen Formulation in the Pesticide Transmission Process and Its Impact on Biological Activity.

Cyetpyrafen is a compound that lacks inherent uptake and systemic translocation activity. If mites do not come into direct contact with the pesticide solution on leaves, the efficacy cannot be achieved. Controlling the particle size can potentially play a crucial role in the manifestation of efficacy. In this study, high-throughput formulation technology was used to systematically screen a large number of adjuvants to obtain cyetpyrafen formulations. The particle size of the active ingredient in the formulation was measured. By examining the dynamic light scattering and contact angle, we simulated the actual process of the efficacy transmission of cyetpyrafen formulations against Tetranychus cinnabarinus. Our results showed that the activity of cyetpyrafen increases as the particle size decreases, suggesting that reducing the particle size can enhance the coverage and deposition on crop leaves, and further improve the dispersion efficiency and enhance spreading capabilities. Furthermore, controlling the particle size at 160 nm resulted in an LC50 value of 0.2026, which is approximately double than that of the commercial product. As a novel pesticide for mites, our study presents the most effective cyetpyrafen formulation in practice. Our findings provide valuable insights into controlling other mite species that pose a threat to agricultural products.

Effect of double cracks merge on fatigue crack propagation life of engine heat shield

To prevent overheating of the airframe, an aero-engine is often designed to play a role in shielding heat radiation heat shield. Since the thermal protection system used in this paper is active, it is subject to a cold gas pressure load on the outside and a thermal radiation load from the combustion chamber on the inside. Therefore, the working environment of the heat shield is very harsh. Taking the heat shield of an aero-engine as the research object, the finite element method (FEM) is used to analyze the thermal-mechanical coupling (TMC) of the actual working process of the heat shield, and the mechanical quantities such as the thermal stresses and mechanical stresses are comprehensively analyzed. According to the finite element simulation results, two stress concentrations are obtained near the connecting lug, and the stress concentrations are set as the initial crack insertion locations. Using the theory related to linear elastic fracture mechanics (LEFM) and the Forman-Newman-de Koning (FNK) model, the fatigue crack propagation life (FCPL) and its law of the merged double cracks of the engine heat shield are calculated. The results show that the FCPL of the heat shield decreases nonlinearly and the critical crack length decreases linearly under different working conditions. This law applies not only to single cracks but also to merged double cracks. In terms of FCPL, the merged double cracks are lower than the single crack with a maximum life reduction rate of 70.9%.

Noise adaptive filtering model integrating spatio-temporal feature for soft sensor

Due to uncertain production conditions and external disturbances, there are a lot of noise in the industrial process dataset. Traditional denoising models can only solve a single noise problem. However, the noise in industrial process data has diversity and inhomogeneity. Therefore, the noise adaptive filtering (NAF) model integrating spatio-temporal feature (ST) (ST-NAF) is proposed for the soft sensor, which achieves a balance between noise and data features to reduce the influence of noise on soft sensor results. The gated recurrent unit extracts temporal features of the industrial process data. Then, the dynamically gated graph attention extracts the interaction relationship between monitoring points to obtain spatio-temporal features. Moreover, the NAF converts time-domain features into frequency-domain features, and adaptively selects frequency-domain components with important information through the noise filtering matrix. The selected frequency-domain components are converted to the temporal domain to obtain the denoised spatio-temporal features. Finally, the self-attention learns the dynamic relationships between denoised spatio-temporal features and output variables to predict the key indicator. Compared with other denoising soft sensor models in a public dataset and an actual industrial process dataset, the ST-NAF achieves state-of-the-art results. And the prediction accuracy of the proposed model improved by 4.5% and 10.0% in terms of R2, respectively. Furthermore, the experimental results show that the ST-NAF can adaptively select useful information from industrial noise data to achieve accurate prediction of key indicators.

The effects of indigenous microorganisms and water treatment with ion exchange resin on Cu-Ni flotation performance

Mineral processing utilizes large amounts of water and aims to reduce water consumption by recirculation and closing the water loops. This results in accumulation of chemical and biological contaminants in process water that may have adverse outcomes on the process performance. To optimize water quality suitable for each process step and plant, knowledge of both chemical and biological effects are needed as well as techniques to best remove the contaminants. This study focused on the consequences of microorganisms, enriched from the actual process earlier, on the flotation performance in the multi-metal Kevitsa mine in Northern Finland and the applicability of ion exchange for the removal of dissolved sulfur species and microorganisms from water. The increase of microbial load from the original 106 to added 107 16S rRNA copies mL−1 affected positively the flotation selectivity, especially in the case of nickel. Two tested water types, process water (PW) and final tailings water (FT), behaved slightly differently. In the Cu flotation phase added microorganisms did not affect the Cu recovery of FT but decreased significantly the recovery of Cu in PW. With equal Cu grade, the recovery was as high as approximately 25 percentage points lower. However, added microorganisms in both water types decreased notably the recovery of Ni in Cu concentrate (18 to 37 %-points). At the same time the amount of Ni recovered in the Ni concentrate increased by 18 to 33 %-points with added microorganisms. Visually the froth layer was higher and more stable in the Ni flotation in experiments with added microorganisms compared to experiments without added microorganisms. The concentrations of dissolved sulfate and thiosulfate ions were low in the studied waters compared to operations treating massive sulfide ores and did not significantly affect the flotation performance. For this reason, the IX water treatment was not required for these ions. However, the IX treatment proved to be effective in removing both sulfur species and microorganisms. The use of dissolved air flotation (DAF) was a successful pretreatment for ion exchange in removal of microorganisms. However, microorganisms are not usually taken into consideration when process performance or water cleaning techniques are designed and optimization could result generally in even better outcome.

Research, Power, and Care: Limitations to Collaborative Research with Children and Youth

This article considers the obstacles and opportunities in collaborative action research. It focuses on two examples: a virtual participatory action research with five migrant Latina young women and a participatory action-oriented project in a middle school in Baltimore, Maryland. We argue that intentions alone are not enough to challenge the dynamics of knowledge production. Children and adult researchers continue to interact in the context of hierarchical power structures. Instead of adults “making space” for independent child subjects to participate, we suggest that pedagogies of acompañamiento and ternura, which emphasize nurturing and accompanying participants, are necessary to foster spaces of collaboration. We broaden conversations about critical research methodologies to emphasize actual processes of relationship building in the context of uneven interdependencies and care. We suggest the important role that radical educational pedagogies from Latin America played in shaping our own research approaches.

AGC regulation capability prediction and optimization of coal-fired thermal power plants

The improvement of the AGC regulation capability of thermal power plants is very important for the secure and stable operation of the power grid, especially in the situation of large-scale renewable energy access to the power grid. In this study, the prediction and optimization for the AGC regulation capability of thermal power plants is proposed. Firstly, considering parameters related to the AGC regulation of the thermal power plant, the max-relevance and min-redundancy (mRMR) is used to extract features from historical sequences of the parameters. Next, a model with multi-long short-term neural networks (mLSTM) is constructed to predict the AGC regulation capability; that is, the obtained feature set is considered as the inputs of the first LSTM sub-model to predict future values of the main steam pressure and main steam temperature, which are then utilized as the inputs of the second LSTM sub-model to predict the actual power generation during AGC regulation operation. Then, the AGC regulation index is calculated according to the “management rules of grid-connected operation of power plant in Northern China” and “management rules of auxiliary service of the grid-connected power plant in Northern China” (i.e., “two rules”), and it is then considered as the objective function to be maximized by optimizing the coal feed rate, air supply rate, and feedwater flow rate. Finally, the actual AGC regulation process of a 300 MW coal-fired power plant is used as an application, and the results show that the proposed method can effectively predict and improve the regulation capability when the AGC instruction is received from the power grid.

Synergistic Effects of Multiple Environmental Factors on Degradation of Silicone Rubber Seals under Marine Atmosphere.

In this research, the degradation behavior and failure mechanism of silicone rubber seal rings under the synergistic effects of multiple factors in the marine atmosphere are fully investigated. Firstly, four aging factors of air, temperature, compressive stress, and chemical medium were determined by analyzing the service environment profile of silicone rubber seal under a marine atmosphere environment. Secondly, to better simulate the actual service environment of silicone rubber and shorten the test period, an artificially accelerated aging test was designed and carried out in the laboratory. In this paper, temperature is utilized as the accelerating stress. According to the results of the pre-test, the accelerating stress level is finally determined to be 110-150 ∘C. In addition, the compression set applied is consistent with the constant compression permanent deformation value of 28% of the silicone rubber in the actual service process. Finally, through the macroscopic physical properties and microstructure analysis of the samples before and after aging, the corresponding test results are given, and the failure mechanism is analyzed and discussed in detail. Through the above test results and discussion, it can be concluded that the aging process of multi-factor coupling on the lower silicone rubber seal ring is uneven, and its aging process is not a simple superposition of multiple environmental factors. More importantly, the above test data and results are of great significance for evaluating the service life of silicone rubber seals, which can be utilized in the future to improve the reliability and durability of related equipment in the marine environment.

Application of Diethylenetriaminepenta pentasodium salt as an eco-friendly depressant to effectively improve the flotation separation of scheelite and calcite

Diethylenetriaminepenta (methylene-phosphonic acid) pentasodium salt (DTPMPA), an eco-friendly reagent, was tried for the first time as a depressant for flotation separation of scheelite from calcite. Micro-flotation tests show that DTPMPA can selectively depress the floatability of calcite. In contrast, DTPMPA barely affects the flotation behavior of scheelite. Based on the selective depress effect, floatation separation of scheelite and calcite can be effectively achieved by using DTPMPA as depressant in artificially mixed minerals flotation tests. Based on a series of measurements, it found the surface of calcite was positively charged due to the existence of Ca ion site, which can be chelated with -PO<sub>3</sub>H- functional group on the surface of DTPMPA. In the flotation process, DTPMPA can be chemically absorbed on the surface of calcite to inhibit further collector adsorption. On contrast, little DTPMPA was adsorbed on the surface of scheelite due to the spatial site resistance and electrostatic repulsion induced by surface WO<sub>4</sub><sup>2+</sup>. All in all, these results exhibit DTPMPA has excellent selective depression ability on calcite, which can be potentially applied in the actual scheelite flotation process.

Online Tg estimation for blade manufacturing

Cost reduction is one of the main drivers in the production of wind turbine blades in the last few years. In this direction, the use of intelligent process monitoring to optimize the infusion, curing and bonding by measuring online the actual process can reduce energy and increase productivity by 20% while ensuring product quality. In this framework, durable non-intrusive and disposable sensors have been developed for the monitoring of resin arrival, the resin’s viscosity during infusion and the on-going Tg during curing by measuring the resin’s electrical resistivity and temperature.

基于课程教学视角的大学生科研创新能力提升探究 ——以全英文研究方法课程为例

As an introductory basic course for college students in Chinese-foreign cooperative programs to engage in scientific research, Research Methodology in English is of great significance for improving their scientific research and innovation ability. However, in the actual teaching process, it faces many problems such as uneven language level, difficult teaching content and difficult operation in practical training. Taking the teaching and research reform of this course as an example, this paper aims to improve the teaching quality and enhance students’ scientific research and innovation ability by optimizing teaching objectives, reconstructing teaching content, integrating teaching means, innovating teaching activities, and rebuilding teaching process, and hopes to provide reference for related teaching reform and optimization of the curriculum system of scientific research and innovation ability.

Fatigue crack propagation simulation of airfoil section blade under aerodynamic and centrifugal loads

Cracks in aero-engine blades occur frequently due to high-cycle fatigue, which may cause accidents. Most of the existing studies simulating blade crack propagation are performed based on simplified blade shapes (rectangular, etc) or single loads (tension, bending, torsion, etc). These simplified treatments lead to a large deviation between the simulated crack propagation law and the actual blade propagation process. To fill the gap, the surface crack propagations of airfoil section blades under aerodynamic load, centrifugal load and the combined action of two loads are simulated based on the combined simulation of FRANC3D and ANSYS. The proposed method is verified by comparing the results with those obtained from the literature and experiment, respectively. In addition, the surface crack propagation path and the change of stress distribution during crack propagation under different loads are simulated. The results show that the crack propagates to the trailing edge (TE) and leading edge (LE) under aerodynamic load and centrifugal load, respectively. In addition, the cracks show three-dimensional shape characteristics under a single load. However, the crack propagates approximately along the plane under the combined action of two loads. The study can provide a theoretical basis for cracked blade failure analysis.

Mode transition prescribed performance control of connected hybrid electric vehicles based on driver intention fuzzy prediction

A novel hierarchical mode transition control (NHMTC) algorithm utilizing traffic information is investigated for realizing a superior dynamic and ride comfort performance of a connected hybrid electric vehicle (CHEV). The upper level includes the target vehicle velocity planning by model predictive control (MPC) considering less vehicle jerk based on the vehicle-to-infrastructure (V2I) information and the driving intention prediction by a type-2 fuzzy neural network (T2FNN) model using the planned target velocity. The lower level involves the automatic clutch system’s prescribed performance fixed-time controller (PPFTC) design and the desired velocity of the clutch engagement calculated by the predicted driving intention to improve the clutch position trajectory’s tracking accuracy and stability under the actual mode transition process. The comparison results with existing schemes under a co-simulation environment demonstrate the advantage and effectiveness of the designed NHMTC method.

Improving the mathematical model of a fiber-optic inclinometer for vibration diagnostics of elements in the propulsion system with sliding bearings

The operational capacity of a vessel’s propulsion system (VPS) has an exceptionally large impact on the safety of the ship and shipping as a whole. This requires constant long-term technical diagnostics of VPS elements in order to determine their real resource. First of all, this refers to the bearing units of VPS. The practical use of the concept of continuous diagnostics requires the introduction of the latest means of monitoring the technical condition of VPS, which can significantly increase the reliability of the measurement results. That is why solving the scientific problem of creating diagnostic tools invariant to operating conditions and adapted for continuous, long-term, and reliable monitoring, namely fiber-optic inclinometers (FOI), is relevant. In order to solve the problem, the object of research has been determined – fiber-optic measuring devices for monitoring changes in the geometric position or damping conditions of oscillations in bearing units of VPS elements. The task to improve fiber-optic means was to increase the accuracy of measurement results. The results are in the form of an improved mathematical model of FOI. The difference of the model is the calculation of actual properties of each material layer of the multilayer structure of real fiber-optic waveguides. A distinctive feature of the proposed solution is that the description of the optical-mechanical process in FOI using an improved mathematical model is more accurate and closer to the parameters of the actual process, which are determined experimentally. The results of the research belong to the field of systems and means of technical diagnosis of VPS elements and can be applied primarily on ships, submarines, and vessels of large displacement

Legal Aspects of the Evaluation of Tenders in Public Procurement Procedures in the Polish Mining Industry

Public procurement procedures facilitate the purchase of products, services, or civil works by public administrations. In Poland, they follow the national rules specified in the Public Procurement Act. Public procurement aims to ensure a transparent and competitive purchasing process, effective use of public resources, equal treatment of all tenderers, and supply of the best products and services. Various aspects of tender evaluation often determine public procurement and the actual process. Of fundamental importance are price and quality. The Polish mining industry is very mature and includes many stakeholders, such as underground, surface, and borehole mines. Public procurement in the mining industry is specialised and involves complex contracts between the contracting authority and the contractor. Additionally, the mining industry involves very high-risk levels and requires special safety efforts. Therefore, this article presents the analysis results related to evaluating offers in public tenders in the most prominent Polish enterprises of the mining industry. The results indicated what procedures should be carried out and what offer evaluation criteria are essential. The emphasis was placed on ensuring that the selection of offers in this industry are not based only on one criterion: price.