Geometallurgy integrates aspects of geology, metallurgy, and mine planning in order to improve decision making in mining schedules. A geometallurgical model is a 3D space that is typically synthesized from early-stage small-scale samples and is composed of several metallurgical units, or domains. This work explores the synthesis of a geometallurgical model for a copper deposit using a purely data-driven unsupervised approach. To this end, a dataset of 1112 drill samples is used, which are clustered using different methods, namely, k-means, hierarchical clustering (AGG), self-organizing maps (SOM), and DBSCAN. Two cluster validity indices (Silhouette and Calinski−Harabasz) are used to select the final model. To validate the potential of the proposed approach, a simulated economic evaluation is conducted. Results demonstrate that k-means exhibits a better performance in terms of modeling and that using the obtained geometallurgical model for mining scheduling increases the project’s Net... [more]

Threaded fastening operations are widely used in assembly and are typically time-consuming and costly. In low-volume, high-value manufacturing, fastening operations are carried out manually by skilled workers. The existing approaches are found to be less flexible and robust for performing assembly in a less structured industrial environment. This paper introduces a novel algorithm for detecting the position and orientation of threaded holes and a new method for tightening bolts. First, the elliptic arc fitting method and the three-point method are used to estimate the initial position and orientation of the threaded hole, and the force impact caused by switching from the free space to the constrained space during bolt tightening is solved. Second, by monitoring the deformation of passive compliance, the position information is introduced into the control process to better control the radial force between the bolt and the threaded hole in the tightening process. The constant force contr... [more]

The drying kinetics of banana slices were examined in a forced convection dryer using an infrared camera to monitor the temperature profile and drying kinetics under control conditions. The air temperature was tested at 40 °C, 50 °C, 60 °C, and 70 °C and the air velocity at 0.2 m/s, 0.5 m/s, and 0.75 m/s, with initial moisture contents of the banana ranging from 76−80% wet basis. The thicknesses of the banana slices being dried were 2, 4, 6, and 8 mm. The optimum drying conditions for the highest drying rate and best color were found to be a temperature of 70 °C, an air velocity of 0.75 m/s, a low relative humidity of 5 to 7%, and banana slices with a thickness of 2 mm. As the air temperature increased, the drying rate and shrinkage also increased. Shrinkage varies concerning moisture loss, and the reduction in radial dimension of banana slices was around 17−23% from the original slice before drying. An empirical mathematical equation was derived by applying the technique of multiple l... [more]

Total phenolic content (TPC), total flavonoid content (TFC), antioxidant and antimicrobial in vitro activity of ethanolic (EE) and hydroethanolic (HE) extracts of mango peel Ataulfo were evaluated. The highest TPC, TFC and antioxidant capacity were as shown in EE. Ethanolic extract was incorporated into ground beef at 1000 (BBEA) and 2000 mg/kg meat (BEEB) concentrations and then compared with 250 mg of sodium ascorbate/kg meat (ASC) along with a control (without antioxidant). The effects of adding EE on instrumental colour, metmyoglobin content, thiobarbituric acid reactive substances (TBARS), pH, microbial load and sensorial analysis of ground beef were evaluated for 11 days at 4 °C. BEEB added in raw ground beef improved colour stability while the lipid oxidation in raw and raw-cooked ground beef was inhibited with a greater antioxidant effect than ASC and a similar overall acceptability score (cooked ground beef). However, incorporating BEEB into ground beef did not show significan... [more]

Hydraulic fracturing is one of the main ways to increase oil and gas production. However, with existing methods, the diameter of the nozzle cannot be easily adjusted. This therefore results in ‘sand production’ in flowback fluid, affecting the application of hydraulic fracturing. This is because it is difficult to identify the one-dimensional series signal of fracturing fluid collected on site. In order to avoid ‘sand production’ in the flowback fluid, the nozzle should be properly controlled. Aiming to address this problem, a novel augmented residual deep learning neural network (AU-RES) is proposed that can identify the characteristics of multiple one-dimensional time series signals and effectively predict the diameter of the nozzle. The AU-RES network includes three parts: signal conversion layer, residual and convolutional layer, fully connected layer (including regression layer). Firstly, a spatial conversion algorithm for multiple one-dimensional time series signals is proposed,... [more]

Hybrid grid-connected renewable energy systems have gained significant importance in sustainably responding to an increased electrical energy demand. These are time-varying nonlinear dynamical plants, where the value of their parameters depends on changing weather conditions and the alternating grid voltage with randomly fluctuating amplitude. This paper proposes a robust cascade MRAC for nonlinear plants representing a class of these systems, which includes n renewable energy converts and a DC/AC single-phase full bridge inverter. The proposal reduces commissioning time by avoiding linearization and knowledge of the plant parameters. Moreover, it includes specific formulas for tuning the controller parameters that decrease their adjustments based on trial and error. Finally, it uses a direct adaptive method with adaptive laws having σθ modification and an inner loop at least five times faster than the outer loop. The proposition validation includes the theoretical stability proof base... [more]

Aeroengine mainshaft bearings are key components in modern aeroengines, and their main functions are to support the rotation of the main shaft of the aeroengine in harsh environments, such as high temperature, heavy load, high speed and oil break; reduce the friction coefficient during the high-speed rotation of the main shaft; and reliably ensure the rotation accuracy and power transmission of the aeroengine’s main shaft during operation. The manufacture of aeroengine mainshaft bearings requires complex processes and precise machining to ensure high performance and reliability, and how to intelligently complete the production and manufacture of mainshaft bearings and ensure the strength and accuracy of the bearings, quickly distinguish the fault types of the bearings and efficiently calculate, analyze and predict the life of the bearings are the current research hotspots. Therefore, building a high-fidelity and computationally efficient digital twin life cycle of aeroengine mainshaft... [more]

Different extraction techniques were used to exploit fruit processing residues for their use as a source of phenolic compounds. Three different extraction methods, namely microwave-assisted extraction (MAE), subcritical water extraction (SWE), and maceration (M), were assessed to gauge their respective efficacies. Total phenolic content (TPC) and total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and radical scavenging activity ABTS assay were evaluated. High-performance liquid chromatography was used to assess the polyphenolic profile. MAE was the extraction technique that allowed the highest recovery of polyphenolic compounds. Concerning the fruit by-products analyzed, the extract of pomegranate peels obtained using M60C and MAE had the highest TPC (313 ± 24 mg GAE/g dry weight (dw)) and TFC (36.0 ± 2.8 mg EE/g dw), respectively, and the highest antioxidant activity (FRAP = 740 ± 67 mg AAE/g dw and ABTS (628 ± 27 mg TE/g dw) corresponded to M60C. The phenolic co... [more]

Orange peels, generally considered as waste, were treated with subcritical water (SWE)—a green technology and environmentally friendly extraction process—at different temperatures (120−200 °C) and extraction times (5−60 min). The extracts which were obtained were chemically and biologically characterised to evaluate this potential source of bioactive compounds. The extracts total phenolics content (TPC) and total flavonoids contents (TFC), as well as total antioxidant capacity (TAC), DPPH radical scavenging activity, and total carbohydrate content, were determined by UV spectrophotometry. The pectin content was quantified by a gravimetric method. The dietary fibre content was investigated, and a phytochemical screening assay was performed. The extract obtained at 120 °C for 5 min displayed the highest TPC (45.45 mg GAE/g DW), TFC (9.29 mg RE/g DW), and TAC (130.47 mg AAE/g DW), indicating that relatively low temperatures and extremely short extraction times can be used in SWE to obtain... [more]

Coal gasification is recognized as the core technology of clean coal utilization that exhibits significant advantages in hydrogen-rich syngas production and CO2 emission reduction. This review briefly discusses the recent research progress on various coal gasification techniques, including conventional coal gasification (fixed bed, fluidized bed, and entrained bed gasification) and relatively new coal gasification (supercritical water gasification, plasma gasification, chemical-looping gasification, and decoupling gasification) in terms of their gasifiers, process parameters (such as coal type, temperature, pressure, gasification agents, catalysts, etc.), advantages, and challenges. The capacity and potential of hydrogen production through different coal gasification technologies are also systematically analyzed. In this regard, the decoupling gasification technology based on pyrolysis, coal char−CO2 gasification, and CO shift reaction shows remarkable features in improving comprehensi... [more]

Silicon is considered to have significant potential for anode materials in lithium−ion batteries (LIBs) with a theoretical specific capacity of 4200 mAh g−1. However, the development of commercial applications is impacted by the volume shift that happens in silicon when charging and discharging. In this paper, a yolk−shell−structured Si@void@C anode material has been developed to address this problem. The silicon nanoparticle yolk material is obtained by recycling kerf loss (KL) Si waste from the process of slicing silicon block casts into wafers in the photovoltaic industry; the carbon shell is prepared by a hydrothermal method with glucose, and the sacrificial interlayer is Al2O3. The produced material is employed in the production of anodes, exhibiting a reversible capacity of 836 mAh g−1 at 0.1 A g−1 after 100 cycles, accompanied by a Coulomb efficiency of 71.4%. This study demonstrates an economical way of transforming KL Si waste into materials with an enhanced value for LIBs.

Fluid components and systems are major components of modern mechanical equipment and have been widely used in various fields such as engineering machinery, rotating machinery, and hydraulic machinery [...]

Conveyor belts are widely used in ore transportation in large-scale mines for their long transportation range, high safety, and strong economic applicability. Coal mine belt conveyors are not only traditional, simple mechanical conveying devices but also automatic control system operating devices that integrate safety, stability, and low power consumption. In the process of coal mining, a conveyor belt control system also needs to be closely integrated with modern industrial systems and information systems, which greatly improves its work efficiency. The purpose of this article is to improve the methods for designing automatic control systems for electric motors in order to obtain mechanical characteristics close to a constant power line, which would ensure the reliable operation of belt conveyors. An automatic control system was designed based on the controller Siemens S7-1200; then, a mathematical model of an automated electric drive was developed. Based on the mathematical model, a... [more]

The new energy context since 2021 has led to dramatic increases in the energy bills of agribusinesses, affecting the price of foodstuffs. A considerable part of energy consumption is due to the heating of water at high temperatures. The present study analyzed the feasibility of using a Solar Water Heating System (SWHS) with an evacuated tube collector. In particular, the required sizing changes, potential savings and cost-effectiveness were analyzed. The results show that the new energy context makes the SWHS investment highly attractive: a payback of less than 4 years in most of the scenarios analyzed; energy savings of more than 60% in the scenarios with higher irradiation; a reduction in total energy expenditure of more than 50% in the favorable scenarios close to the current reality. The new context especially favors cold and temperate climates, with very sharp drops in payback compared to the previous situation. To achieve these values, it is necessary to design an optimized sizin... [more]

Cranioplasty or cranial reconstruction is always a challenging procedure even for experienced surgeons. In this study, two different design techniques for customized cranial prostheses are assessed for cranial reconstruction. Mirror reconstruction is one of the commonly used reconstruction techniques that fails when cranial defects cross the midline of symmetry. Hence, there is a need for a design technique for the reconstruction of cranial defects irrespective of their location on the symmetrical plane. The anatomical reconstruction technique demonstrates its applicability for a wide spectrum of complex skull defects irrespective of the defective position in the anatomical structure. The paper outlines a methodological procedure involving a multi-disciplinary approach involving physicians and engineers in the design and reconstruction of customized cranial implants for asymmetrical skull defects. The proposed methodology is based on five foundation pillars including the multi-discipli... [more]

Shale reserves have become an ever-increasing component of the world’s energy map. The optimal design of multi-well multi-stage fracturing (MMF) treatments is essential to the economic development of such resources. However, optimizing MMF treatments is a complex process. It requires geomechanical simulation, reservoir simulation, and automatic optimization. In this work, an integrated workflow is proposed to optimize MMF treatments in an unconventional reservoir, and the net present value (NPV) of reserves was treated as the objective function. The forward model consists of two submodels: a hydraulic fracturing model and a reservoir simulation model. The stochastic simplex approximation gradient (StoSAG) is used with the steepest ascent algorithm to maximize the NPV function. The computational results show that optimizing the fracture design can achieve a 20% higher NPV than that obtained with the field reference case. The drainage area of the optimal design is larger than that of the... [more]

Deep reservoirs are in a high-pressure and high-temperature (HPHT) environment, while the experimental conditions for rock electrical properties that meet the deep reservoir conditions are harsh and costly. Although digital rock technology can simulate the electrical properties of rocks, it is limited to electrical simulation studies under normal temperature and pressure conditions (NPT), which limits their ability to capture the electrical characteristics of deep hydrocarbon reservoirs. This limitation affects the accuracy of saturation prediction based on resistivity logging. To simulate the rock electrical properties under HPHT conditions, we proposed a low-cost and high-efficiency HPHT digital rock electrical simulation workflow. Firstly, samples from deep formations were CT-scanned and used to construct multi-component digital rocks that reflect the real microstructure of the samples. Then, mathematical morphology was used to simulate the overburden correction under high-pressure... [more]

The application of liquid−liquid chromatography principles to solvent extraction processes in hydrometallurgy can greatly simplify rare earth metal separation technologies by separating multicomponent mixtures in one technological operation. In this study, the chromatographic separation of rare earth elements (REEs) in multistage extraction columns was experimentally studied under conditions of impulse sample injection—single and multiple loading of large volumes of metal salt solution into the installation. The results obtained showed the feasibility of operating sieve plate extraction columns in the liquid−liquid chromatography mode. A closed-loop recycling technology is proposed for the separation of rare earth elements in multistage extraction columns operating in the liquid−liquid chromatography mode. For further development and industrial implementation of this technology, experimental studies should be conducted on intensified multistage extraction columns, such as sectioned col... [more]

Nickel-rich ternary cathode materials (NRTCMs) have high energy density and a long cycle life, making them one of the cathode materials of LIB that are currently receiving much attention. However, it has shortcomings such as poor cycling performance (CP) and a high-capacity decay rate. Because of this, the study analyzed the modification effect of WO3 on NRTCM lithium batteries by preparing WO3-modified poly-crystal and single-crystal NCM622 materials under the existing conditions of better original cathode materials as reference samples. The results showed that in the morphology and structure testing, with the increase of WO3 addition, the c/a values of all NCM622-WO3 samples were greater than 4.95. In the analysis of cycling and rate performance (CRP), as W increased, the rate performance (RP) of the NCM622-W4.0 sample had a discharge specific capacity ratio of 86.2% at 10.0 C/1.0 C. In cyclic voltammetry testing, when the addition amount of WO3 was 1.0%, the polarization degree of S... [more]

In this paper, the two-dimensional Kelvin−Helmholtz (KH) instability occurring in the shear flow of polymer fluids is modeled by the dissipative particle dynamics (DPD) method at the coarse-grained molecular level. A revised FENE model is proposed to properly describe the polymer chains. In this revised model, the elastic repulsion and tension are both considered between the adjacent beads, the bond length of which is set as one segment’s equilibrium length. The entanglements between polymer chains are described with a bead repulsive potential. The characteristics of such a KH instability in polymer fluid shear flow can be successfully captured in the simulations by the use of the modified FENE model. The numerical results show that the waves and vortexes grow more slowly in the shear flow of the polymer fluids than in the Newtonian fluid case, these vortexes become flat, and the polymer impedes the mixing of fluids and inhibits the generation of turbulence. The effects of the polymer... [more]

Antibiotics are often prescribed to treat infections caused by group B Streptococcus; however, inappropriate use of antibiotics can develop resistance. Because of this, the research was carried out with the aim of evaluating the in vitro effect of the hydroalcoholic extract of Caesalpinia spinosa (Molina) Kuntze known as Taya or Tara on the viability of β-hemolytic streptococci; an experimental investigation of increasing stimulation was carried out. The hydroalcoholic extract of C. spinosa pods was worked in concentrations of 250, 500, 750, and 1000 mg/mL, which were placed on filter paper discs to perform the sensitivity test following the Kirby−Bauer method. The greatest inhibition of bacterial viability was observed in the penicillin control group (GPT-01) followed by the TCT-04 group (hydroalcoholic Tara extract 1000 mg/mL). In addition, it was found that these groups are statistically different from the rest (p < 0.05), while the lowest bacterial inhibition was obtained for th... [more]

The purpose of the study was to identify and predict the optimized parameters for phosphoric acid production. This involved modeling the crystal reactor, UCEGO filter (as a detailed model of the filter is not available in Aspen Plus or other simulation software), and acid separator using Sci-Lab to develop Cape-Open models. The simulation was conducted using Aspen Plus and involved analyzing 10 different phosphates with varying qualities and fractions of P2O5 and other minerals. After a successful simulation, a sensitivity analysis was conducted by varying parameters such as capacity, filter speed, vacuum, particle size, water temperature for washing the filtration cake, flow of recycled acid and strong acid from the separator below the filter, flow of slurry to reactor 1, temperature in reactors, and flow of H2SO4, resulting in nearly one million combinations. To create an algorithm for predicting process parameters and the maximal extent of recovering H3PO4 from slurry, ANN models we... [more]

Class and shape transformation functions are proposed to carry out the parametric design of the blade profiles because fan efficiency is closely related to the shape of blade profiles. An optimization with the objectives of fan efficiency and static pressure based on the Kriging models was established, and numerical simulation data were applied to construct the Kriging models. The dissipation function was used to analyze the fan energy loss. The prediction results show that the maximum accuracy error between the Kriging model and the experimental data is approximately 0.81%. Compared with the prototype fan, the optimized fan was able to ameliorate the distribution of the flow field pressure and velocity; the outlet static pressure increased by 9.03%, and the efficiency increased by 2.35%. The dissipation function is advantageous because it can intuitively indicate the location and amount of energy loss in the fan, while effectively obtaining the total energy loss as well. The situation... [more]

The working conditions and environment of coal mine shafts are intricate and special. Currently, manual inspections or fixed-point monitoring is generally applied for daily safety monitoring, and intelligent and automated inspection equipment and its supporting technologies are not available. Starting from the technical requirements of the electromagnetic adsorption device of the wall-climbing robot for safety monitoring of the coal mine shaft, based on the structural characteristics and chemical composition of the composite shaft lining of the coal mine, the fundamental structure of the electromagnetic array and the electromagnetic unit are clarified, and a multi-layer matrix simulation point overlap mapping analysis method is proposed. Based on the system modeling and simulation calculations in MATLAB software, the number and distribution law of effective mapping points between the endpoints of the electromagnetic array and the reinforced frame in the shaft lining are inferred, which... [more]

Three green algae, collected from the Romanian Black Sea coast, are studied: Ulva lactuca, Enteromorpha intestinalis, and Cladophora vagabunda, which were collected from six different coastal areas. This paper aims to identify the bioactive compounds of these green algae and their beneficial properties, in order to use them as potential nutraceuticals using different analytical methods. Pharmacognostic, microbiological, and physico-chemical methods used for the analysis of algal materials revealed a rich and diverse array of biocompounds with nutritional value. In the case of green algae, a high percentage of sulphates, carbohydrates and dietary fibers were identified. Moisture, ash, total nitrogen, protein and lipid contents were determined. The contents of pigments, vitamins, and metals determined complement the nutritional qualities of the three seaweed species studied as future nutraceuticals. The content of flavonoid and phenolic compounds identified in the composition of seaweeds... [more]