Processes

As technology advances, electronic circuits are more vulnerable to errors. Soft errors are one among them that causes the degradation of a circuit’s reliability. In many applications, protecting critical modules is of main concern. One such module is Fast Fourier Transform (FFT). Real FFT (RFFT) is a memory-based FFT architecture. RFFT architecture can be optimized by its processing element through employing several types of adder and multipliers and an optimized memory usage. It has been seen that various blocks operate simultaneously in many applications. For the protection of parallel FFTs using conventional Error Correction Codes (ECCs), algorithmic-based fault tolerance (ABFT) techniques like Parseval checks and its combination are seen. In this brief, the protection schemes are applied to the single RAM-based parallel RFFTs and dual RAM-based parallel RFFTs. This work is implemented on platforms such as field programmable gate arrays (FPGAs) using Verilog HDL and on application-specific integrated circuit (ASIC) using a cadence encounter digital IC implementation tool. The synthesis results, including LUTs, slices registers, LUT–Flip-Flop pairs, and the frequency of two types of protected parallel RFFTs, are analyzed, along with the existing FFTs. The two proposed architectures with the combined protection scheme Parity-SOS-ECC present an 88% and 33% reduction in area overhead when compared to the existing parallel RFFTs. The performance metrics like area, power, delay, and power delay product (PDP) in an ASIC of 45 nm and 90 nm technology are evaluated, and the proposed single RAM-based parallel RFFTs architecture presents a 62.93% and 57.56% improvement of PDP in 45 nm technology and a 67.20% and 60.31% improvement of PDP in 90 nm technology compared to the dual RAM-based parallel RFFTs and the existing architecture, respectively. Full article

To explore the flotation feasibility and flotation law of iron minerals from amphibole-type iron oxide ore with full-size minerals, a systematic study on the flotation behaviors of single minerals hematite, quartz, and amphibole was carried out with the anionic reverse flotation system. The effects of collectors, depressants, activators, and pH on the floatabilities of three single minerals was investigated. The flotation separations of binary mixed minerals and ternary mixed ores were carried out, respectively. The study results show that CaCl₂ is adsorbed on the surfaces of quartz and amphibole, which can activate them. The hydroxyl groups of the starch molecular chain were adsorbed on the surfaces of the hematite and amphibole in the form of hydrogen bonds, but were hardly adsorbed on surface of the quartz. Therefore, both hematite and amphibole were depressed, resulting in a poor separation effect of the three single minerals in the anionic flotation system. Full article

CO₂ pre-injection fracturing is a promising technique for the recovery of continental shale oil. It has multiple advantages, such as oil recovery enhancement, CO₂ geological storage and water consumption reduction. Compared with conventional CO₂ huff and puff and flooding, CO₂ pre-injection features higher injection rates and pressures, leading to EOR and improved CO₂ storage performance. Combining physical experiments and numerical simulation, this research systematically investigated the EOR and storage performance of CO₂ pre-injection in continental shale reservoirs. The results showed that CO₂ pre-injection greatly improved the oil recovery; after seven cycles of soaking, the average oil recovery factor was 39.27%, representing a relative increase of 31.6% compared with that of the conventional CO₂ huff and puff. With the increasing pressure, the CO₂ solubility grew in both the oil and water, and so did the CO₂ adsorption in shale. Numerical simulation indicated that the average CO₂ storage ratio of the production stage was 76.46%, which validated the effectiveness of CO₂ pre-injection in terms of CO₂ geological storage. Full article

The design of distillation columns significantly impacts the economy, energy consumption, and environment of chemical processes. However, optimizing the design of distillation columns is a very challenging problem. In order to develop an intelligent technique to obtain the best design solution, improve design efficiency, and minimize reliance on experience in the design process, a design methodology based on the GA-BP model is proposed in this paper. Firstly, a distillation column surrogate model is established using the back propagation neural network technique based on the training data from the rigorous simulation, which covers all possible changes in feed conditions, operating conditions, and design parameters. The essence of this step is to turn the distillation design process from model-driven to data-driven. Secondly, the model takes the minimum TAC as the objective function and performs the optimization search using a Genetic Algorithm to obtain the design solution with the minimum TAC, in which a life-cycle assessment (LCA) model is incorporated to evaluate the obtained optimized design solution from both economic and environmental aspects. Finally, the feasibility of the proposed method is verified with a propylene distillation column as an example. The results show that the method has advantages in convergence speed without sacrificing accuracy and can obtain an improved design solution with reduced cost and environmental impact. Compared with the original design using rigorous simulation, the TAC is reduced by 6.1% and carbon emission by 27.13 kgCO₂/t. Full article

The power quality estimation for distribution network connected DG (distributed generation) is important in the power system. The significance testing for power quality indicator is less used in traditional power quality evaluation. However, the power quality indicator is affected by various factors of the power system, which seriously impact the power quality evaluation result. To solve this problem, A novel power quality comprehensive estimation model based on multi-factor variance analysis for distribution network with DG is proposed in this paper, in which the significance testing is carried out for power quality indicator with the various system factors, and then to generate the evaluation weights in different levels, further to obtain the power quality assessment results for single node. And then, the dual-significance tests are carried out to generate the weight of node and to obtain the comprehensive estimation result of whole system. At last, an example is developed to validate that, compared with the traditional power quality evaluation, the proposed method is more reasonable and effective in the power quality evaluation for DG connected distribution network. Full article

The conventional methods for producing large-diameter pipes, such as extrusion and winding fusion welding, suffer from various drawbacks including difficulties in forming, complex molds, and high costs. Moreover, the flexibility and production efficiency of traditional manufacturing processes are relatively low. To address these challenges, this study proposes a new manufacturing process for polymer melt jetting and stacking based on fused deposition modeling (FDM) and rolling forming principles. This innovative approach aims to overcome the limitations of conventional methods and improve the flexibility and production efficiency in large-diameter pipe manufacturing. In the polymer melt jetting and stacking process, a plastic melt with a specific temperature and pressure is extruded by an extruder. The melt is then injected through the nozzle embedded in the previous layer of the pipe blank. By utilizing the localized rolling action of the forming device and adjusting the diameter using a diameter adjustment device, the newly injected plastic melt bonds with the previous layer of the pipe blank. Finally, the continuous large-diameter plastic pipe is formed through cooling and solidification. Experimental investigations demonstrate that the polymer melt jetting and stacking process can produce pipes with diameters ranging from 780 mm to 850 mm and thicknesses of 20 mm to 25 mm. The radial tensile strength, impact strength, and microstructural orientation of the produced pipes exhibit superior performance compared to those in the axial direction. Additionally, process parameters such as rolling speed, cooling temperature, melt extrusion speed, and tractive velocity significantly influence the microstructure and mechanical properties of the pipes. Full article

Traditional food packaging materials maintain food quality and safety during storage, but they cause significant environmental pollution. For this reason, there has been an increased demand in designing packaging materials from biodegradable ingredients such as edible proteins and polysaccharides. In the current study, biodegradable coatings from gelatin (Gel) or gelatin–rice starch (Gel-RS) mixtures were applied to fresh-cut Colocasia (Colocasia esculenta) and potato (Solanum tuberosum) samples, and main quality properties such as weight loss, firmness, breaking force, and color were evaluated during storage for seven days at 5 °C. Gel-coated potato samples kept moisture at higher levels compared to untreated samples or Gel-RS-coated samples (weight loss 41.40 ± 3.33%), while no differences in weight loss were observed for all fresh-cut Colocasia samples. Furthermore, the gelatin–rice starch coating increased the breaking force (1181.40 ± 159.3) and hardness (1609.6 ± 76.79) of fresh-cut potato samples during storage conditions. On the other hand, fresh-cut Colocasia coated with gelatin and gelatin/rice starch showed no significant differences in weight loss and texture characteristics. In conclusion, gelatin and gelatin/rice starch coatings provoke preservation of quality characteristics during storage of fresh-cut potatoes but have no preservation effects on fresh-cut Colocasia. This research enriches the knowledge of the effects of biodegradable coatings on fresh-cut starchy tubers. Full article

Landfills have long been widely used to dispose of Municipal Solid Waste (MSW). However, many landfills have faced early closure issues in recent years due to overload operations. Although in-situ aeration technology can quickly stabilize MSW, low oxygen utilization rates present a general problem that results in high energy-consuming and operating costs. This research aims to improve oxygen utilization efficiency by observing the dynamic respiratory index and the removal of contaminants. Three continuous reactors were constructed and designed with targeted aeration and re-circulation schemes for different landfill ages. The results show that a well-designed aerobic, semi-aerobic, and anaerobic reactor can fully degrade the organic components of MSW with different landfill ages, and the quantity of waste has been reduced by more than 60%. Additionally, it was disclosed that gas-water joint technology has a promotional effect on activating microorganisms. Full article

A new fault location method based on the three-terminal travelling wave method is proposed for the fault location problem of multi-branch overhead line–cable transmission lines. Firstly, the process of fault travelling wave propagation in overhead transmission lines and the phenomenon of refraction are analysed, and an improved phase-mode transformation is introduced to decouple the electromagnetic coupling and perform fault phase selection. Secondly, the Pearson correlation coefficient is introduced to compare the similarity of the current travelling waveforms at different measurement points in order to implement fault segmentation. To solve the problems of the complexity of the fault travelling wave propagation process and the difficulty of identifying the travelling wavehead, the Hilbert–Huang transform is used to extract the fault signal characteristics, and the travelling wave arrival moment is accurately calculated by the sampling error correction method to determine the fault location. Finally, the accuracy and stability of the method are verified via a simulation test on the MATLAB/Simulink platform. The results show that the proposed positioning method combining the three-terminal travelling wave method with HHT and sampling error correction can locate the fault location more accurately, and it has good potential for application in the engineering field. It provides a new technical means for fault location in overhead transmission lines, which is expected to become one of the most important technologies in the future power system. Full article

The catalytic activity of metal oxides in the processes of low- and high-temperature oxidation (LTO and HTO, respectively) of oil was studied on model systems consisting of oil-saturated quartz sand with additives of Al₂O₃, Cr₂O₃ and MgO using thermal analysis methods. The used additives were shown to shift the LTO and HTO processes to the low-temperature region. The catalytic activity of a natural reservoir carbonate rock without and with water was studied. This study established that at room temperature in dry carbonate rock, the oil components undergo dealkylation and polycondensation of aromatic fragments for a week. In the presence of water, the polycondensation processes are suppressed, and the cracking of resin and asphaltene occurs. The cracking reactions lead to a decrease in the content of heteroatoms in resins and asphaltenes. Full article

Bolted joints are widely used in aeroengine rotor systems to connect multiple components into an integrated structure and provide sufficient stiffness. The mechanical properties of a bolted joint have a significant effect on rotor dynamics. For modern aeroengine designs, the blade-tip clearance is gradually reduced to improve efficiency, which may lead to rubbing damage and affect safe operation. The mechanical properties of a bolted joint change significantly during the blade–casing rubbing process and influence the dynamic properties of the rotor system. Based on the finite element (FE) modeling method, a 15-node bolted joint rotor system model is established in this paper, in which the bolted joint is represented by a 2-node joint element, and the blade–casing rubbing force is considered. The Newmark method is used to solve the motion equations. The dynamic model is validated by comparing the frequency response characteristics for different numbers of blades with the results provided in other published studies. Based on the established model, the effects of the rotational speed, number of blades, and rubbing stiffness on the dynamic responses, normal rubbing forces, and bending stiffness of the bolted joint are evaluated by numerical simulation. The results show that the response amplitude and bending stiffness of the bolted joint change significantly under blade–casing rubbing faults, and the mean value of the vibration response deviates significantly from 0 as the number of blades increases. Meanwhile, the amplitude of the frequency component f_VC and the maximum value of the normal rubbing force also increase as the number of blades increases. The main contribution of this paper is the establishment of a new model for a bolted joint rotor system, considering the time-varying bending stiffness of the bolted joint and the blade–casing rub fault, comparing the simulation results to obtain some general results bridging the current research gap. Meanwhile, the numerical results in this paper can provide a cognitive basis for the blade–casing rubbing fault mechanism of a bolted joint rotor system under the influence of speed, number of blades, and rubbing stiffness. The nonlinear dynamic characteristics observed in the present paper can be applied to the blade–casing rubbing fault diagnosis of turbomachines. Full article

Water contamination with various contaminants, including organic species, is a global concern. Reclamation through safe, economic and technically feasible methods is imperative. Two perovskites, zinc titanate (ZnTiO₃) and manganese titanate (MnTiO₃), mixed with TiO₂ phases, were prepared as nano-powders and nano-films. The materials were characterized and used as catalysts in photodegradation of aqueous methylene blue, a hazardous model contaminant, using solar simulated radiation. The effects of various reaction conditions on the photodegradation were examined. The kinetics indicated the suitability of using the process at various contaminant concentrations and catalyst loadings. Both powder and film catalysts completely removed the contaminant in less than 6 h. Powder and film forms of the MnTiO₃ mixture were more efficient than their ZnTiO₃ counterparts. In both perovskite mixtures, the films exhibited higher catalytic efficiency than the powders. The film materials exhibited high catalytic efficiency in both the continuous flow and batch processes. Water contaminated with various methylene blue concentrations can be treated by the film catalysts that can be recovered and reused with no technical difficulties. The results open new horizons for larger-scale water purification processes. Full article

The increase in non-point source (NPS) pollution from agricultural cultivation and production sources has been cited as one of the main reasons for water eutrophication. This study built a national NPS database and estimated the nutrient (including both nitrogen (N) and phosphorus (P)) balance and NPS pollution of crop farming at the county level in 2015. Finally, the NPS pollution risks were assessed, and relative policy suggestions were provided. The results indicated that (1) in 2015, the total amounts of N and P surpluses in China were 7.95 and 7.39 million tons, respectively. The south of the Yangtze River had a relatively higher nutrient surplus compared to that in northern China. (2) The NPS emissions for N and P in China were 168.84 × 10⁴ tons and 8.93 × 10⁴ tons, respectively, with the highest NPS loads occurring in the eastern part of the Sichuan Basin, southern China and southwestern China, while the lowest loads occurred in northeast China. (3) The potential risk assessment results showed that a broad division emerged at the Yangtze River basin, with the northern area under lower risk than the southern area. This estimation work can provide guidance and technical support for local government and policy makers to control NPS pollution. Full article

Data management systems are increasingly used in industrial processes. However, data collected as part of industrial process operations, such as sensor or measurement instruments data, contain various sources of errors that can hamper process analysis and decision making. The authors propose an operating-regime-based data processing framework for industrial process decision making. The framework was designed to increase the quality and take advantage of available process data use to make informed offline strategic business operation decisions, i.e., environmental, cost and energy analysis, optimization, fault detection, debottlenecking, etc. The approach was synthesized from best practices derived from the available framework and improved upon its predecessor by putting forward the combination of process expertise and data-driven approaches. This systematic and structured approach includes the following stages: (1) scope of the analysis, (2) signal processing, (3) steady-state operating periods detection, (4) data reconciliation and (5) operating regime detection and identification. The proposed framework is applied to the brownstock washing department of a dissolving pulp mill. Over a 5-month period, the process was found to be in steady-state 32% of the time. Twenty (20) distinct operating regimes were identified. Further processing with the help of data reconciliation techniques, principal component analysis and k-means clustering showed that the main drivers explaining the operating regimes are the pulp level in tanks, its density, and the shower wash water flow rate. Additionally, it was concluded that the top four persistently problematic sensors across the steady-state spans that would need to be verified are three flow meters (06FIC137, 06FIC152, and 06FIC433), and one consistency sensor (06NIC423). This information was relayed to process experts contacts at the plant for further investigation. Full article

Poly-o-chloroaniline (POCA) and Mn₂O₃/β-MnO₂/POCA porous nanocomposite are both synthesized using oxidative polymerization, with K₂S₂O₈ and KMnO₄ as oxidants, respectively. The materials are characterized to confirm their optical, morphological, crystalline, chemical, and elemental properties. The nanocomposite exhibits superior optical properties compared to POCA. The promising optical characteristics make the nanocomposite an attractive candidate for light-sensing applications. Through electrical estimation, the nanocomposite photodetector displays the highest sensitivity between 340 and 440 nm, with J_ph (current density) of 0.14 and 0.13 mA cm⁻², correspondingly, and an estimated photon number of 7.4610²¹ and 6.93 × 10²¹ photons/s, respectively. At 340 and 440 nm, the calculated photoresponsivity (R) values are 0.73 and 0.64 mA W⁻¹, respectively, while the estimated detectivity (D) values are 1.64 × 10⁸ and 1.45 × 10⁸ Jones, respectively. These promising results indicate that the fabricated photodetector can soon potentially estimate light wavelengths and photon numbers in various industrial applications. Full article

The sandstone reservoirs of the He8 member within the Lower Permian Shihezi Formation are important targets for oil and gas exploration in the southern Ningwu Basin. This study utilized thin-section identification, scanning electron microscopy, and X-ray diffraction analysis to examine the petrological features and reservoir characteristics, and evaluate the impact of the mineral composition and diagenesis type on the porosity of the sandstone reservoir. Additionally, a multiple linear regression prediction model was developed to predict the distribution of promising sandstone reservoirs in the study area. The results of the analysis revealed that the sandstone of the He8 member is mainly composed of feldspathic lithic sandstone, followed by lithic sandstone. The main reservoir type is characterized by secondarily dissolved pores and micropores within kaolinite aggregates. The low porosity (ranging from 0.2% to 10.7%) and permeability indicate that the He8 member is a tight sandstone reservoir. This reservoir has undergone compaction, cementation, and dissolution diagenesis, and is presently in the stage of mesodiagenesis B. The rigid framework of quartz, the dissolution of feldspar grains, and the intergranular pores of kaolinite are significant contributors to reservoir quality and the main drivers of porosity. In this study, a multivariate linear regression model was developed based on the mineral content of quartz, feldspar, carbonate minerals, kaolinite, smectite, and rock fragments, which accurately predicts the porosity of the studied reservoirs. Based on this model, it was predicted that the north of the Jingle South sub-depression contains a favorable reservoir space in the tight sandstone reservoir of the He8 member. The findings of this study hold significant reference value in the quantitative characterization of tight sandstone reservoirs with similar depositional and diagenetic characteristics, and improving the prediction effect of favorable reservoirs. Full article

Pulsed Laser Deposition (PLD) is a highly flexible experimental methodology for the growth of thin films of a broad variety of materials, based on the generation of laser-induced plasmas (LIP) with material ablated from a solid target and on the transfer of the ablated material to a substrate. This review is focused on carbon-based materials—specifically, diamond-like carbon (DLC), graphene and carbyne—and will both discuss the influence of the most critical experimental parameters on the obtained materials and present the experimental developments proposed in the recent literature to tailor the properties of the deposited films and optimize the standard PLD technique for production of various carbon-based materials. Full article

Tectonic coal seams are characterized by soft, low permeability and high gas outburst. The traditional gas control method is the intensive drilling and extraction in this seam, which is not only large in engineering quantity, high in cost, difficult to form holes and low in extraction efficiency, but also easy to induce coal and gas outburst, which is a difficult problem for global coal mine gas control. To solve this difficult problem, the controllable shockwave equipment developed by the author’s team and successfully applied in the practice of permeability enhancement of coal seam, combined with the principles of shock vibration sound wave generation and shock wave attenuation and evolution in the rock stratum, a new idea of loading a controllable shock wave in the roof and floor of coal seam is proposed. The shock wave first attenuates and evolves into a high-strength sound wave in the roof and floor rock stratum, and then enters and loads into the coal seam to achieve the purpose of increasing permeability without damaging the physical properties of the tectonic coal seam and facilitating the opening of the original fractures. According to the new technical ideas, the implementation scheme and key parameters of the gas pre-extraction models in tectonic coal seam are designed, including the penetration drilling, roof and floor horizontal holes, shield tunneling and the high-strength acoustic wave of the working face, which provides a new technical approach to solve the problem of high efficiency and low cost gas extraction in the tectonic coal seam. Full article

Previous studies have established that the selection of gas extraction borehole parameters is crucial for the effectiveness of gas extraction. To more accurately determine the reasonable extraction radius of gas extraction boreholes in the coal seam, this study was based on the actual occurrence conditions of the coal body. A coal-seam gas-seepage model, considering dynamic changes in permeability under gas–solid coupling conditions, was constructed. It was combined with FLAC^3D numerical simulations to develop a borehole extraction model closer to the field’s natural needs. The study revealed the influence of borehole diameter and spacing on gas extraction, obtained the radius of effect of borehole extraction, and optimized the gas extraction borehole parameters based on data simulation experiments. Multiple sets of experimental results indicated that the optimal parameters are a borehole diameter of φ = 113 mm and a borehole spacing of 5 m. Applying these parameters in on-site tests at the 14,303 working faces of a particular mine significantly improved gas extraction efficiency, with a 29.7% increase in gas extraction concentration. This verified the accuracy of the simulation results and provides a scientific basis for cost reduction and efficiency enhancement in wellbore mining. Full article