Small Depth Research Articles

Increasing the operating time of pumping units of water-reducing wells through the use of self-cleaning filters

Relevance. At enterprises engaged in open-pit mining, water-reducing wells equipped with submersible installations of electric submersible pumps are widely used in drainage systems. A significant content of particles of mechanical impurities in the pumped-out well fluid causes intense hydro-abrasive wear of the working stages of the electric submersible pumps. Among the existing methods of combating hydro-abrasive wear of submersible pumps in water-reducing wells, the simplest, most economical and effective is the use of filters of various designs. An urgent task is to increase the operating time of submersible electric submersible pumps while reducing the time and costs for cleaning or replacing filters. Aim. Justification of the designs and operating parameters of a self-cleaning filter and tubing string extension included in the electric submersible pump assembly of a dewatering well. Methods. Static calculations of deformation of the tubing column and the tubing column extension under the influence of overpressure. Results and conclusions. The authors have carried out the analysis of an electric submersible pump functioning in the dewatering wells of quarries during the development of mineral deposits by the open method. It was revealed that the main reason for the failure of the electric submersible pumps is the hydro-abrasive wear of the working stages of the submersible pump. The authors propose a method to increase the operating time of the electric submersible pumps in dewatering wells complicated by intensive removal of particles of mechanical impurities by using a self-cleaning filter of the original design. It is noted that a promising direction of development of the drive for self-cleaning filters is the use of deformation of the tubing column. Based on the calculations carried out, it was concluded that the small depths of dewatering wells cause an insufficient amount of deformation of the tubing string to clean the filter element. To increase the length of the reciprocating movement of the electric submersible pumps relative to the production string of a dewatering well, it is proposed to use a tubing string extension of an original design. The operating parameters of the tubing string extension were calculated, which showed the possibility of providing the required amount of controlled reciprocating movement of the electric submersible pumps in the well to restore the throughput of a self-cleaning filter.

Comparison of GIS-based solutions for the assessment of lakes water volume: a case study of biosphere reserve "Shatskyi"

Understanding the volume of water in a lake is essential for assessing the health of the eco-system. Geographic Information Systems offer valuable tools for evaluating water volume in lakes, employing such methods as remote sensing for surface data and bathymetric surveys for lakebed data. By integrating techniques like sonar-based bathymetric surveys, precise depth measurements can be obtained to accurately calculate water volume. Based on the survey results, depth maps of three lakes of different sizes, depths, and origins within the Biosphere Reserve were created. Key morphometric characteristics and the volume of water mass were calculated from these surveys. However, it is important to note that these investigations can be expensive and time-consuming, especially for large lakes. It may not be feasible for lakes in remote or inaccessible areas. Hollister JW's (2010) bathymetry modelling method was applied, as an alternative to ground-based bathymetry survey results, to calculate the water volume of the above-mentioned lakes. The method is based on the assumption that the depth of the reservoir is a function of distance from the shoreline. The advantage of the method is the limited amount of input data, namely the area and maximum depth of the reservoir. The modeling bathymetry method is not suitable for very deep lakes like Svitiaz Lake, with complicated lake basin shapes, as demonstrated by comparing the results with ground-based bathymetric survey data. The lake with the smallest depth and more regular lake basin form, which is closer to a circular shape, such as Liutzimer Lake, provided the best results. Using the bathymetric modelling approach for other medium and small Bioreserve lakes could help to define the characteristics of water bodies for which this method can be extremely useful.

Comparison of clinical features of patients with or without severe gastrointestinal complications in aggressive gastrointestinal lymphomas.

Aggressive primary gastrointestinal non-Hodgkin lymphoma (PGINHL) is an uncommon and heterogeneous group of lymphoid malignancies, that differs from indolent lymphoma and has a high incidence of severe gastrointestinal complications (GICs). To investigate and compare the clinicopathological characteristics, treatments and outcomes in the GICs and No-GICs group with aggressive PGINHL. This retrospective analysis was performed on aggressive PGINHL patients between January 2013 and December 2021 at our hospital. The independent influence factors of GICs were obtained by univariate and multivariate Logistic regression analysis, the selected variables significantly related to GICs were selected as the final predictors to construct nomogram. Kaplan-Meier curves further analyzed the survival of patients in GICs and No-GICs groups. Survival analysis of GICs group was performed using Cox regression. We focused on 124 aggressive PGINHL cases, which had a relatively high incidence 48.4% (60/124 cases) of GICs, the most common histological type in GICs group was diffuse large B-cell lymphoma (DLBCL) (n = 49, 81.7%). In the GICs group, small intestine was the most common anatomic site of lesion (43.3%), followed by large intestine (31.7%), and then stomach and esophagus (25.0%). Multivariate Logistic regression analysis showed that the independent risk factors for GICs were the small intestine [odd ratio (OR) = 3.33; 95% confidence interval (CI): 1.47-9.41; P = 0.009), aggressive B-cell (OR = 0.09; 95%CI: 0.01-0.83; P = 0.033), maximum tumor diameter (OR = 1.25; 95%CI: 1.07-1.47; P = 0.005), invaded deep serous layer (OR = 3.38; 95%CI: 1.24-9.19; P = 0.017). We developed a nomogram to predict risk of GICs in aggressive PGINHL patients based on independent risk factors. The value of area under curve calculated by receiver operating characteristic curve was 0.815, and calibration curve and decision curve analysis further indicated that the prediction effect was superior. The majority of patients with GICs were given combination therapy (chemotherapy combined with surgery or radiation). Event-free survival and overall survival in GICs group were no worse than those in the No-GICs group. The complication rate of GICs in patients with aggressive PGINHL was relatively high, particularly in PGI-DLBCL. The independent risk factors for GICs were the small intestine, PGI-TNKL, bulky tumor, and depth of invasion. A combination treatment, involving surgery, improved survival in the GICs group.

The sedimentology and multi-stage evolution of a Pleistocene esker on soft substratum, a case from North Central Poland

Eskers are one of the meltwater landforms that enable the reconstruction of the nature of subglacial drainage systems. Therefore, they play a significant role in the study of palaeo ice sheets. While the spatial distribution of subglacial tunnels and their geometry resulting from the geomorphological features of eskers are relatively well known, the course and time of sedimentation processes taking place inside the subglacial conduits are understood only to a certain extent, especially in the case of eskers developed on soft substrata. The paper presents an example of an esker that developed on a soft substratum from Central-North Poland, which was formed in several stages. In the initial stage, meltwater drainage took place through a channel that dissected the substratum (N-channel). Its development was associated with intense flow under pressure, but the sediments filling the channel were already deposited under atmospheric pressure when the flow used only part of the available space of the conduit. The high frequency of large-scale, cross-stratified lithofacies indicates significant flow depth and sediment deposition under a lower flow regime. The succession filling the channel resembles the sediments of a low-sinuosity open river systems with varied channel morphology, however, it also contains deposits like the point bar succession. Later, the R-channel developed, dominated by deposition from supercritical flows, probably of a much smaller depth. The sediments were deposited from a traction carpet or a highly turbulent suspension. The massive structure of many lithofacies indicates that flow overload was common. The transformation of the system from N-channel to R-channel was probably related to the decrease in the slope of the ice sheet surface during ablation, which resulted in a reduction of the potential hydraulic pressure gradient. The final stage of esker sedimentation was associated with deposition in an open channel, which indicates the passive nature of the marginal part of the ice sheet.

Prediction of chaotic dynamics and extreme events: A recurrence-free quantum reservoir computing approach

In chaotic dynamical systems, extreme events manifest in time series as unpredictable large-amplitude peaks. Although deterministic, extreme events appear seemingly randomly, which makes their forecasting difficult. By learning the dynamics from observables (data), reservoir computers can time accurately predict extreme events and chaotic dynamics, but they may require many degrees of freedom (large reservoirs). In this paper, by exploiting quantum-computer ansätze and entanglement, we design reservoir computers with compact reservoirs and accurate prediction capabilities. First, we propose the recurrence-free quantum reservoir computer (RF-QRC) architecture. By developing quantum feature maps and removing recurrent connections, the RF-QRC has quantum circuits with smaller depths. This allows the RF-QRC to scale well with higher-dimensional chaotic systems, which makes it suitable for hardware implementation. Second, we forecast the temporal chaotic dynamics and their long-term statistics of low- and higher-dimensional dynamical systems. We find that RF-QRC requires smaller reservoirs than classical reservoir computers for higher-dimensional systems and the same predictability. Third, we apply the RF-QRC to the time prediction of extreme events in a model of a turbulent shear flow with turbulent bursts. We find that the RF-QRC has longer predictability than the classical reservoir computer for extreme events forecasting. The results and analyses indicate that quantum-computer ansätze offers nonlinear expressivity and computational scalability, which are useful for forecasting chaotic dynamics and extreme events. This work opens new opportunities for using quantum machine learning on near-term quantum computers. Published by the American Physical Society 2024

Simultaneous cutting and grinding of micropins using cylindrical microtools

Decreasing cutting force is always crucial in cutting processes. One method to achieve this is by minimizing tool wear, for which rotary cutting is a highly effective technique. The use of a cylindrical tool offers the additional benefit of easy tool fabrication, which is especially advantageous for a microtool capable of machining micropins. However, there have been no reported studies on rotary cutting using a cylindrical microtool. It should be noted that if a microtool is fabricated by electrical discharge machining, it is expected to engage in cylindrical grinding as well. This suggests that both rotary cutting and cylindrical grinding can be carried out simultaneously; however, there have also been no reported studies on simultaneous cutting and grinding. Therefore, the present study investigated whether this machining method can perform micropin machining, if it actually involves both cutting and grinding actions, and whether the combination of these actions enhances material removal capability. In turning and grinding experiments, where only one of the tool and workpiece was rotated, both actions were observed. Furthermore, it was confirmed that micropin machining can be performed by rotating both the tool and workpiece, resulting in a decrease in machining force to approximately one-quarter to one-half compared to that of turning. This indicates that simultaneous cutting and grinding was carried out, and the overlap of their actions enhanced material removal capability. In addition, the relationship between the machining conditions and machining force was investigated. At a small depth of cut, a tool with smaller surface roughness exhibited lower machining force than a tool with larger roughness, and the opposite was true at a large depth of cut. Finally, an ultrasmall-diameter micropin with a diameter less than 3 μm was successfully machined using conditions capable of reducing machining force.

A novel classification of dyslipidaemia through the analysis of five million lipid profiles: an unsupervised machine learning approach

Abstract Background Dyslipidemia encompasses a wide range of lipoprotein disorders categorised through two classifications (Fredrickson-Levy [FL] or Sniderman).(1,2) However, both classifications are criticised for relying on incomplete knowledge of lipoprotein metabolism, especially with the emergence of novel treatment options and variations in individual treatment responses.(3) Clustering, an unsupervised machine learning (ML) algorithm that can process a wide range of variables, has the potential to unmask patient groups with distinct molecular profiles and unique therapeutic targets that can inform more effective prevention strategies for cardiovascular disease (CVD).(4) Aim We aimed to use unsupervised ML algorithms to discover intrinsic dyslipidaemia categories from lipoprotein measurements, recognise the necessary components of lipid panels for classification, and analyse the similarities between the newly formed clusters, FL and Sniderman classifications. Methods Lipid profiles of 5,080,248 patients were obtained from the ‘Very Large Database of Lipids’ database. This yielded up to 78 blood components per patient, including at least 31 lipoprotein variables. The analysis involved unsupervised K-means clustering with optimised values for K and the subset of variables, determined in an unsupervised manner using a suitable measure of complexity. We then interpreted our clusters using probabilistic decision trees to provide compact and interpretable representations. Finally, we compared the clusters with Sniderman and FL categories. Results In a completely unsupervised fashion, we identified 14 clusters that could be matched to Sniderman categories. The confusion matrix showed total agreement of 76% (see Figure 1, left panel), relative Cohen’s kappa of 0.78 (the relative version captures accuracy on categories containing smaller numbers of patient profiles) and an accuracy of 96% on the small Type III class. Similar results were observed when matching to FL types. We accurately represented our clusters using probabilistic decision trees of small depth (see Figure 2). We discovered that the data had low intrinsic dimension and a manifold-like structure in which the different clusters could be illustrated (see Figure 1, right panel). Specifically, only 3 variables were needed to obtain our classification: apolipoprotein b, total cholesterol and triglycerides. Conclusion We showed that completely unsupervised ML techniques can uncover dyslipidaemia categories in lipoprotein profiles from a large patient population. The categories largely align with existing classifications based on prior knowledge of lipoprotein metabolism. Furthermore, few lipoprotein variables were required for categorisation (low-dimension data), which could aid in determining which lipoproteins should be measured in a clinical setting. Further analysis of the differences between ML clusters and traditional classifications is needed, which may enhance CVD risk management.

Structural Features of Porous Silicon Formed on Heavily Doped Plates of Single-Crystal Silicon with Electron Conductivity

Using scanning electron microscopy, the structures of the surface and internal regions of porous silicon obtained by anodizing heavily doped plates of single-crystal silicon with electron conductivity in a hydrofluoric acid solution at different current densities were studied. It is found that the porous silicon surface has dark gray and light gray pores, which differ in size and surface distribution density. Dark gray pores possess larger sizes, and their density is about 5–10 times less than that of light gray pores. Based on the cross-section imagery, it is shown that light gray pores correspond to underdeveloped channels of small depth, while dark gray pores are the entrance points of deep bottle-shaped channels passing from the surface into the depth of the silicon wafer. The equivalent diameters of light gray pores on the surface of porous silicon are 12–15 nm and are practically independent of the anodic current density. At the same time, the equivalent diameters of dark gray pores and average distances between their centers increase linearly from 15 to 35 nm on the surface and from 35 to 120 nm in the volume of porous silicon when the current density is increased from 30 to 90 mA/cm2. The average thickness of silicon skeleton elements is about 3 nm on the surface and increases to 5–6 nm in the volume. By setting the density of the anode current, it is possible to obtain layers of porous silicon with different structural parameters. The obtained research results have practical significance for the formation of composite materials based on porous silicon, which can be used as a porous matrix for the deposition of metals and semiconductors.

Geophysical investigation of the ground fissures and ground subsidence near Karla lake (eastern Thessaly basin, Greece)

Ground fissures have occurred in the last four decades across the eastern Thessaly basin (Greece) resulting in damage to the villages of the area. Several studies for the area refer to the over-pumping of ground water as the main reason for their occurrence, causing sediment compaction due to the reduction of the aquifer level. In this paper, we depict the results of a joint geophysical survey trying to determine the subsurface regime of the basin and the exact reasons contributing to the existence of the ground fissures. The focal part of the survey includes gravity measurements for deeper investigation, combined with existing and already presented geoelectrical and electromagnetic data. Several borehole data have also been used for the calibration of the geophysical interpretation. The differential GNSS data of the gravity campaign revealed the ground subsidence of the area, reaching up to 9.16 m. The alpine basement of the area is comprised mainly of metamorphic rocks, such as marbles, mica schists and gneiss-schists, covered by thick fluviοterrestrial and alluvial deposits. Several structural maps were generated in order to delineate the lateral density variations that could be related to fault zones along with the interpretive sections for geological modelling. The alpine bedrock was adumbrated in relatively great depths, with a large anticline of NW-SE direction, rising and separating the basin in two parts. In the east part, the fluvioterrestrial deposits, which are expected to play an important role in the compaction due to their water aquifer, are located only west of this anticline. At the east part, where the old lake Karla was hosted, the alluvial deposits lay directly on the alpine basement in smaller depths. This complicated regime is responsible for differential sediment compaction and the ground subsidence of the surface.

Evaluation of the soil quality using health index in temperate European conditions (Slovak Republic)

Land users and policy makers recognize importance of soil health and these types of evaluations are welcomed within sustainable land management. The aim of this study was to establish minimum and maximum values of soil health index across the breadth of agricultural used soils of Slovakia. Core objectives included (1) identifying the range of soil health benchmarks; (2) defining benchmarks for different land uses, and (3) defining benchmarks of soil health index for main groups of agricultural soils in Slovakia. These benchmarks represent the first soil health metrics of their kind in Slovakia using data from 266 locations. The soil health index (SHI) approach has been used as a quantitative tool to establish linkage between soil health and soil ecosystem services. We recorded the highest average SHI value in the very warm climatic region of the Slovak Republic, where the majority of agriculturally used arable soils (with an optimal pH value without contamination) are located. The locality with lowest SHI value is in a slightly warm area on soil used as arable soil with a very small depth of humus horizon, with by the pH value in an acidic area, and with a high content of clay. The typical SHI in humus-rich soil groups of Slovakia (Mollic Fluvisols, Chernozems and Cutanhic Luvisols) is higher contrasted with the typical SHI in other soil groups of Slovakia.

Accurate Modelling of AFM Force-Indentation Curves with Blunted Indenters at Small Indentation Depths.

When testing biological samples with atomic force microscopy (AFM) nanoindentation using pyramidal indenters, Sneddon's equation is commonly used for data processing, approximating the indenter as a perfect cone. While more accurate models treat the AFM tip as a blunted cone or pyramid, these are complex and lack a direct relationship between applied force and indentation depth, complicating data analysis. This paper proposes a new equation derived from simple mathematical processes and physics-based criteria. It is accurate for small indentation depths and serves as a viable alternative to complex classical approaches. The proposed equation has been validated for ℎ < 3R (where h is the indentation depth and R is the tip radius) and confirmed through simulations with blunted conical and pyramidal indenters, as well as experiments on prostate cancer cells. It is a reliable method for experiments where the tip radius cannot be ignored, such as in shallow indentations on thin samples to avoid substrate effects.

Design of a Novel Microlens Array and Imaging System for Light Fields.

Light field cameras are unsuitable for further acquisition of high-quality images due to their small depth of field, insufficient spatial resolution, and poor imaging quality. To address these issues, we proposed a novel four-focal-square microlens and light field system. A square aspheric microlens array with four orthogonal focal lengths was designed, in which the aperture of a single lens was 100 μm. The square arrangement improves pixel utilization, the four focal lengths increase the depth of field, and the aspheric improves image quality. The simulations demonstrate pixel utilization rates exceeding 90%, depth-of-field ranges 6.57 times that of a single focal length, and image quality is significantly improved. We have provided a potential solution for improving the depth of field and image quality of the light field imaging system.

Effects of dietary propyl gallate and Lactobacillus plantarum addition on growth, intestinal morphology, antioxidant capacity, and immune functions of Pekin ducks

The interaction between probiotic bacteria and polyphenol antioxidants can potentially enhance animal health. The present study examined the effects of propyl gallate and Lactobacillus plantarum supplementation on the growth, intestinal morphology, antioxidant capacity, and immune functions of Pekin ducks. A total of 128 male Pekin ducks (7-day-old) were allocated to four treatment groups with four replicates of eight birds each. The ducks were fed the corn-soybean based diet (the control), supplemented with either propyl gallate (100 mg/kg), Lactobacillus plantarum (4 × 109 CFU/kg), or both, for 5 weeks. Dietary supplementation with propyl gallate and Lactobacillus plantarum had no significant effect on feed intake (P > 0.05), but increased average daily gain (P < 0.05). Lactobacillus plantarum also reduced the feed/gain ratio (P < 0.05). Villus height (VH) in the duodenum and ileum was increased by supplementation, while only propyl gallate supplement increased VH in the jejunum (P < 0.05). Supplementation had no effect on small intestine crypt depth (P > 0.05). Enhanced total superoxide dismutase activity was observed with supplementation (P < 0.05), but no effects were seen on catalase, malondialdehyde, total antioxidant capacity, and glutathione peroxidase values (P > 0.05). Serum immunoglobulin G was increased with Lactobacillus plantarum (P < 0.05), but not with propyl gallate (P > 0.05). No change in IgA and IgM concentrations was observed with supplementation. In conclusion, dietary supplementation with propyl gallate, Lactobacillus plantarum, or both, enhanced the villus height of the small intestines, improving the growth rate of Pekin ducks. The synergistic effects of both propyl gallate and Lactobacillus plantarum on the villus height and serum total superoxide dismutase activity surpassed the individual effects of each supplement in Pekin ducks.

A Nanorod With Near-Perfect Absorption for Efficient Utilization of Solar Thermal Energy

Solar thermal utilization faces a significant challenge, with efficient photothermal conversion being the primary issue. Although plasma nanofluid-based direct absorption solar collectors have shown potential in providing excellent sunlight capture capabilities, their narrow-band absorption limits their efficient photothermal conversion. This study proposes an alternative solution by introducing gold nanorods that achieve nearly perfect absorption across 300–1100 nm. The study demonstrates that the spectral absorption capacity of nanorods remains unaffected by their size and material at specific concentrations and depths. The analysis of the electromagnetic distribution at the resonance absorption peak reveals that the nanorods exhibit a “lightning rod” effect and surface plasmon resonance, leading to significant absorption. Additionally, the study investigates the effect of five common plasma nanomaterials on the nanorods’ optical absorption properties. The results show that titanium nitride-based nanorods exhibit broad-spectrum absorption and require only a small concentration and depth to achieve a 95% solar weighted absorption fraction. This research provides a valuable guide for the efficient photothermal conversion of plasma nanofluids, enhancing their potential for solar thermal systems.

Metoda za postizanje značajnih sila sidrenja unutar ograničenih dubina ugradnje u tanke betonske ploče i ljuske ojačane vlaknima

Contemporary fibre-reinforced concrete provides new opportunities for the design of thin concrete elements with substantial bending strength. To realise the full benefits of reduced weights owing to the reduced structural thickness, new anchorage elements must be developed that can sustain high anchorage forces within limited embedment depths in thin plates. This paper introduces a new anchorage design for concrete plates or shells that provides high tensile forces between 4 and 6 kN within a small embedment depth of 5 mm. The proposed design concept includes a two-stage anchorage mechanism that provides the required tensile strength and ductility for the anchorage. Achieving such anchorage capabilities within the limited embedment depth of thin concrete elements enables the production of lightweight concrete plates and shells.

Machine learning-based prediction of statically equivalent seismic forces in pin-supported cylindrical reticulated shells

Reticulated shells exhibit complex vibrations during earthquakes, encompassing components in horizontal and vertical directions, and multiple vibration modes occur. In particular, single-layer reticulated shells with a small depth relative to their span exhibit many vibration modes, and the shapes of these modes can vary depending on the geometry. The method for rapidly setting equivalent static seismic forces remains unexplored. In response to the above background, this study proposes a novel approach for calculating the seismic forces on single-layer reticulated shells using machine learning techniques. The shells in focus are pin-supported cylindrical reticulated shells, typically for the roofs of gymnasiums used as evacuation facilities during severe earthquakes in Japan. Machine learning uses numerical analysis results for approximately 20,000 shells, with varied spans, half-open angles, and aspect ratios. A method for preprocessing the principal vibration modes as image data is proposed, after which the imaged vibration modes are predicted from the shape parameters of the shell using a neural network. The prediction accuracy is analyzed, and a method for rapidly calculating seismic loads based on combining predicted vibration modes is proposed. These seismic loads are compared with the response spectrum method results, and their effectiveness is discussed.

Impact Resistance Performance and Damage Characteristics of Mortise-and-Tenon Joint Prefabricated Bridge Piers

The mortise-and-tenon joint prefabricated connection combines the assembly form of mortise-and-tenon joints and cast-in-place wet joints. It achieves reliable joint connections through small joint depths and lap-spliced reinforcement lengths. To study the impact resistance and damage characteristics of the assembled pier, a nonlinear finite element analysis was performed on the assembled and monolithic pier model piers to study the effects of mortise-and-tenon joint depths, lap reinforcement, and grout on the response of the piers to vehicle impact. The results showed that, after impact, the damage to the prefabricated pier was similar to that of the monolithic one. The failure mode involved opening of the seam at the impact face-pier bottom junction and localized concrete compression at the back-impact face pier bottom, and damage accumulated from the column base towards the column centerline. The mortise-and-tenon joint provided substantial horizontal constraint for the pier, imparting excellent resistance to lateral stiffness. Consequently, both piers showed nearly identical peak impact forces, yet the prefabricated pier exhibited a lesser degree of bending deformation compared to the monolithic one. The depth of the mortise-and-tenon joints was a critical factor affecting the impact response of the prefabricated bridge pier. When the depth reached 0.4D or more, it ensured good impact resistance and joint connection, enhancing energy absorption capability and reducing pier damage. The length of lap-spliced reinforcement significantly affected the overall integrity of prefabricated component connections. Lap lengths of 10d or more greatly reduced the probability of failure in the connection between pier columns and cap beams, lowering damage to the pier columns, joints, and pier cap beams, thus ensuring good impact resistance. The diameter of the lap-spliced reinforcement and the elastic modulus of the grouting material affected the local stiffness near the joints. Increasing the diameter of the lap-spliced reinforcement appropriately prevented excessive local damage, while altering the elastic modulus had minimal impact on improving pier damage.

CFD-DEM study on the raceway transport phenomena and thermo-chemical behaviors in a three-dimensional blast furnace: Effects of process parameters

An in-depth exploration of the kinetic behaviors of the raceway can provide practical insights for optimizing blast furnace (BF) operations. In this study, the transport phenomena and thermo-chemical behaviors in the raceway of a three-dimensional BF were simulated from particulate scale by using the discrete element method-computational fluid dynamics (DEM-CFD) approach. The effects of process parameters (blast velocity, oxygen concentration, blast temperature, coke size and distribution, tuyere insertion depth, and tuyere inclination) on coke combustion characteristics (mass fraction distributions of gas species and reaction kinetics rate) and thermo-chemical behaviors (particle volume fraction, raceway size, mass loss, and coke temperature) were investigated. Meanwhile, microstructures of coke bed were analyzed, and correlations were established for raceway size prediction. The results indicate that the mass fraction distributions of O2 and CO are similar, both showing balloon-like shapes. The distributions of both the CO2 mass fraction and the kinetic rates of reactions exhibit annular shapes. The raceway size increases or even overlaps with increasing blast velocity/oxygen concentration/PSD standard deviation of coke and decreasing blast temperature/coke size. Too large or too small tuyere insertion depth or tuyere inclination is not conducive to the formation of the raceway. Besides, the mass loss, temperature, and microstructures also vary with the process parameters. RSM model can well predict the raceway depth, width, and height. This study extends the particle-scale model by considering transport phenomena towards the global perspective of a real BF, and the obtained new findings on the complex reacting behaviors in the raceway will provide better insights into the optimization of the BF process.

University experiences of students and graduates with neurodiversity: tools for creating a specialized mentoring program related to working life

IntroductionThe term neurodiversity encompasses a range of conditions, including autism, attention deficit and hyperactivity disorder, dyslexia, and dyscalculia. In higher education, students with these conditions often face barriers that hinder their optimal academic performance. These barriers stem from their specific needs and institutional requirements. This situation can also negatively impact their ability to transition into the workforce. Therefore, it is necessary to design strategies that ensure specialized support for this population, guided by the opinions of neurodiverse students. The objective of this study is to identify the needs, difficulties, and tools related to the transition into the workforce, as reported by neurodiverse students and graduates from the bachelor's degree in psychology program, who present some conditions of neurodiversity.MethodsFor this purpose, a qualitative/phenomenological research was carried out.ResultsThe gathered opinions revealed that the main needs of students include the following: increased awareness and capacity within higher education institutions for timely diagnosis, the implementation of reasonable adjustments for better integration into their activities, provision of supportive environments, the development of strategies to enhance cognitive and emotional aspects, such as planning skills, time management, and emotional regulation skills.DiscussionThe results of this study are consistent with other studies that emphasize the importance of creating a compassionate pedagogy in educational settings. This involves a greater commitment from educators to address and improve pedagogical practices, provide necessary tools, and develop strategies to help students with neurodiversity conditions throughout their careers. The limitations of this study include the small sample size and restricted depth of the interviews. Therefore, future research should increase the number of participants and explore the interviews in greater depth.

Controllable diamond cutting of structured surfaces with subnanometric height features on silicon

Diamond cutting with a controllable depth of cut at the subnanometric scale is desired for next-generation electronics and optics. However, due to the limits of positioning accuracy of the current machine tools, diamond cutting at subnanometric scale depths remains in realm of molecular dynamic (MD) simulations instead of engineering realization. Cutting force feedback and control is regarded as a potential method to improve the positioning accuracy of machine tools. In this study, an ultra-precision force feedback loop with the resolution down to submillinewton is employed and integrated on an ultra-precision machine tool to enable the capability of cutting at subnanometric scale depth. By this way, the relationship between the cutting force and such small depth of cut needs to be well studied. MD simulations are conducted in this study to analyze the mechanism of material removal and influence of the crystallographic effect on the actual cutting depth and force caused by varied cutting directions at subnanometric to nanometric scale depth in diamond turning. Then, the crystallographic effect of silicon with the depth of cut from subnanometric to nanometric scale is compensated experimentally for accurate cutting at such an extremely small scale. Controllable diamond cutting of structured surfaces with actual depths and amplitudes ranging from several angstroms to a few nanometers on silicon is successfully realized.