Entire Cross Section Research Articles

Preparing large-scale, uniform, and high-performance Cu–Cr–Zr strips by a novel continuous expanding extrusion process

A novel continuous expanding extrusion process for manufacturing Cu–Cr–Zr strips was proposed in the present study. The U-shaped strips with a cross-section of 420 mm × 19 mm were successfully prepared by taking the upward continuous casted Φ 28 mm rods as raw material. Electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) were employed to characterize the microstructure and precipitates, respectively, which revealed that the microstructure of the continuous extruded strip is very fine and uniform across the entire cross-section and the Cr precipitates are in a dispersed distribution in the matrix helping to improve the strength of the alloy. The average grain size is approximately 1 μm and much smaller than that of the as-cast state (in millimeters). The average micro-hardness, tensile strength, and electrical conductivity of the extruded strip are 120 HV, 328.8 MPa, and 82.6 % IACS, respectively, increasing approximately by 31.6 %, 29.3 %, and 125.5 % in comparison to these of the as-cast state. In addition, the fracture elongation can maintain a very high level (average value ∼28.9 %). The strengthening mechanisms were then quantitatively calculated, which showed that grain boundary strengthening, precipitation strengthening, and dislocation strengthening take comparable contributions. Thus, our investigations provide new insights into manufacturing high-performance Cu–Cr–Zr strips.

Electromechanical behavior and damage index system of 3D carbon fiber angle-interlock woven composites with FEA and data processing tools

The relationship between structural damage and electrical resistance change of carbon fiber reinforced composites is important to structural health monitoring. Here, we investigated the electromechanical behavior and damage index system for identification of various damage types in 3D angle-interlock woven composites under tensile loading in the warp direction. The mechanism of electrical resistance change was explored by combining current injected from both ends (Electrical current is in the plane of the laminate and goes through the entire cross section of the specimen) and current injected diagonally (Direction of electrical current between the in-plane direction and the through-thickness direction). A finite element model was established to analyze the electric potential distribution and tensile damage evolution process of composites. We found current injected from both ends can only detect with yarn damage and current injected diagonally can detect with matrix cracks, interface cracking and yarn damage. Based on the electrical resistance data of current injected diagonally, we used principal component analysis and K-means clustering methods to establish a damage index system to reflect the damage accumulation degree of different damage modes. The finite element analyses verified the rationality of the damage index system.

Microstructure features and mechanical properties of non-heat treated HPDC Al9Si0.6Mn–TiB2 alloys

This study aimed to enhance the mechanical properties of high pressure die casting (HPDC) Al9Si0.6Mn alloys by incorporating in-situ TiB2 particles. The effects of TiB2 addition on the microstructure and mechanical properties of as-HPDC Al9Si0.6Mn alloys were investigated. The results showed that TiB2 addition refined the bimodal grain structure and eutectic Si morphology in the central region of the as-HPDC alloys, which was the primary contributor to the mechanical properties. The thickness of the skin region and band zone increased with increasing TiB2 addition, while the central region exhibited a reduced thickness but remained dominant on the entire cross-section. The optimal TiB2 content was found to be 1 wt%, resulting in the 23.4 % reduction in grain size and 10.7 % enhancement in yield strength. The modified strengthening model based on the microstructure features of the central region accurately predicted the yield strengths of as-HPDC alloys. Finally, the morphological strengthening factors induced by TiB2 particles were analytically illustrated in the HPDC Al9Si0.6Mn–TiB2 alloys.

Numerical modelling of a large-diameter sealing structure in a deep radioactive waste repository

Numerical modelling of a large-diameter sealing structure in a deep radioactive waste repository

Development of the hydrological regime of the Uzh River under backwater conditions to minimize the urban environment risks

The impact of high dams with large reservoirs with long-term regulation is covered in the scientific literature quite widely. The information and recommendations on the use of low-head dam for the creation of the low backwater are not enough. Large dams reduce the mean annual flow downstream, the magnitude and frequency of floods, lead to the accumulation of suspended solids, nutrients compounds (nitrogen, potassium, phosphorus), which, together with increasing temperature leads to the “blooming” phenomenon of the reservoir and the overgrowth, create barrier for sediments transferring and fish. The main reason of the deterioration of the water quality is the water retention time in the formed reservoir and anthropogenic pollution, although the literature rarely provides quantitative data of the water retention time for the evaluated reservoir. The environment risks assessment of the impact of the reservoir should include the calculation of the water retention time, the presence of pollutants in the river, which may indicate future negative effects. The hydrological regime of the river after the backwater creation should correspond to the natural flow with the floods passage by the entire width of the river bed, which will significantly improve flood management, sediments transport and washing the river bed. The significant risk is the shallowing of the river downstream, the amount of water discharged into the downstream should be at least 75% of the river flow. Releasing the flow to the downstream with an overflow or through fish passage structures allows to enrich the water with oxygen. In order to preserve biodiversity, it is necessary to create or leave islands and shallow water areas for the needs of waterfowl. To ensure an environmentally friendly regime operation of the low-head dam the crest of the spillway structure should be at the bottom level along the entire cross section. The low-head dam should be provided with automatic control system and communication with the hydrometric station for a quick response to the flow changes in the river.

Membrane Functionalization Approaches toward Per- and Polyfluoroalkyl Substances and Selected Metal Ion Separations.

Adsorption and ion exchange technologies are two of the most widely used approaches to separate pollutants from water; however, their intrinsic diffusion limitations continue to be a challenge. Pore functionalized membranes are a promising technology that can help overcome these challenges, but the extents of their competitive benefits and broad applicability have not been systematically evaluated. Herein, three types of adsorptive/ion exchange (IX) polymers containing strong/weak acid, strong base, and iron-chitosan complex groups were synthesized in the pores and partially on the surface of microfiltration (MF) membranes and tested for the removal of organic and inorganic cations and anions from water, including arsenic, per- and polyfluoroalkyl substances (PFAS), and calcium (hardness). When directly compared with beads (0.5-6 mm) and crushed resins (0.05 mm), adsorptive/IX pore-functionalized membranes demonstrated an increased relative sorption capacity, up to 2 orders of magnitude faster kinetics and the ability to regenerate up to 70-100% of their capacity while concentrating the initial solution concentration up to 12 times. The simple and versatile synthesis approach used to functionalize membranes, notably independent of the polymer type of the MF membrane, utilized pores throughout the entire cross section of the membrane to immobilize the polymers that contain the functional groups. Utilizing the pore volume of commercial membranes (6-112 mL/m2), the scientific weight capacity of the polymer (3.1-11.5 mequiv/g), and the synthesis conditions (e.g., monomer concentration), the theoretical adsorption/IX capacities per area of the membranes were calculated to be as high as 550 mequiv/m2, substantially higher than the 175 mequiv/m2 value needed to compete with commercially available IX resins. This work therefore shows that pore functionalized membranes are a promising path to tackle water contamination challenges, lowering separation diffusion limitations.

Raw data consistent deep learning-based field of view extension for dual-source dual-energy CT.

Due to technical constraints, dual-source dual-energy CT scans may lack spectral information in the periphery of thepatient. Here, we propose a deep learning-based iterative reconstruction to recover the missing spectral information outside the field of measurement (FOM) of the second source-detectorpair. In today's Siemens dual-source CT systems, one source-detector pair (referred to as A) typically has a FOM of about 50cm, while the FOM of the other pair (referred to as B) is limited by technical constraints to a diameter of about 35cm. As a result, dual-energy applications are currently only available within the small FOM, limiting their use for larger patients. To derive a reconstruction at B's energy for the entire patient cross-section, we propose a deep learning-based iterative reconstruction. Starting with A's reconstruction as initial estimate, it employs a neural network in each iteration to refine the current estimate according to a raw data fidelity measure. Here, the corresponding mapping is trained using simulated chest, abdomen, and pelvis scans based on a data set containing 70 full body CT scans. Finally, the proposed approach is tested on simulated and measured dual-source dual-energy scans and compared against existing referenceapproaches. For all test cases, the proposed approach was able to provide artifact-free CT reconstructions of B for the entire patient cross-section. Considering simulated data, the remaining error of the reconstructions is between 10 and 17HU on average, which is about half as low as the reference approaches. A similar performance with an average error of 8HU could be achieved for real phantommeasurements. The proposed approach is able to recover missing dual-energy information for patients exceeding the small 35cm FOM of dual-source CT systems. Therefore, it potentially allows to extend dual-energy applications to the entire-patient crosssection.

TiN inclusions distribution in the composite cross section of Titanium Micro-alloyed Steel slab: thermo-chemical modeling and automatic statistic analysis

A model for TiN (Titanium Nitride) inclusions precipitation was developed to investigate the precipitation and growth behavior of TiN inclusions during slab solidification for the entire cross-section of Titanium Micro-alloyed Steel (0.0077 wt%N, 0.12 wt%Ti) slabs. The model integrates the principles of heat transfer, thermodynamics, and kinetics to predict the size and concentration of TiN inclusions in slabs. The outcomes of the TiN inclusions precipitation model showed that the TiN inclusions size on the surface of the slab was 2.82 μm, the central TiN inclusions size was 10.07 μm, and the total TiN inclusions concentration was 0.073 wt%. The distribution of TiN inclusions in the slabs was ascertained by automated scanning electron microscopy/energy dispersive X-ray spectroscopy inclusion analysis (AZtec Steel system). The results showed a sharp decrease in the number density of TiN inclusions number and an increase in the average size from the surface to the center of the slab. The model validation revealed that the model might accurately simulate the maximum size of TiN inclusions in the slab. However, the presence of micron-sized TiN particles in the steel matrix resulted in an overestimation of the modelled TiN concentration as compared to the actual TiN concentration.

Radiation Shielding Properties of Oxides (Al2O3, PbO and Fe2O3) based on Klein-Nishina Cross-section

In this study, we investigate the Klein-Nishina differential cross-section equation for total cross-section and extend it to calculate the total molecular cross-section for compounds Al2O3, PbO, and Fe2O3. Our findings reveal that the total molecular cross-section of these compounds is significantly larger, with values 5 times greater than the total atomic cross-section. Furthermore, we determine that the molecular cross-section of Al2O3, PbO, and Fe2O3 is 73, 132, and 118 times greater than the total electronic cross-section, respectively, while the atomic cross-section of these compounds is 15, 66, and 24 times greater. At low energy levels ranging from 1-5 MeV, the entire molecular, atomic, and electronic cross-section dominates due to Compton scattering. However, as the photon energy increases, Compton scattering becomes negligible, and a slight contribution from pair production scattering is observed. We also establish the adequate atomic numbers for Al2O3, PbO, and Fe2O3, which are determined to be 15, 66, and 24, respectively. These results highlight the significance of mass attenuation, cross-section, and adequate atomic number in the selection of radiation shielding materials for various protection purposes. The findings from this study provide valuable insights into the properties and behavior of these compounds, enabling informed decisions in radiation shielding applications.

Cross sections, penetrating range and stopping power for charge particles emission from n + 52Cr

In a fusion reactor, DT reactions produce huge amount of neutrons which hit the structure material and produce heat and damages. To understand the production of nuclear heating and material damages, study of double differential cross section (DDX), energy differential cross section (EDX), penetrating range of incident particles and stopping power of target element was calculated for 52Cr(n, p) and 52Cr(n, a) reactions. The calculated data have been compared with the suitable experimental data collected from EXFOR and other. The contribution of compound, pre-equilibrium and direct reaction processes has been analyzed for the entire cross section calculation. The emission of charged particles at different angles has been discussed based on the reaction processes. Parameter adjustment has been applied to fit the experimental data.

Microstructure and Properties of Cr8 Cold Work Die Steel by Spray Forming, Traditional Casting, and Forging

In this paper, DC53 cold work dies steel bars with the same specification (φ150 mm) was prepared by spray forming and traditional casting and forging technology. Through the characterization of microstructures using various methods such as OM, SEM, EBSD, and XRD, the mechanical performance testing of hardness, impact resistance, bending strength, and wear resistance, the microstructure characteristics, and mechanical properties differences between the DC53 cold work die steel produced by the two methods were systematically compared. The experimental results show that in terms of microstructure, the carbides in the DC53 cold work die steel produced by the traditional casting and forging process are distributed in a reticular pattern. While the carbide in the DC53 cold work dies steel produced by the spray forming process is finer and uniformly distributed, with higher uniformity across the entire cross-section. In terms of mechanical properties, the DC53 cold work die steel produced by spray forming exhibits superior hardness, impact toughness, bending strength, and isotropy, while the traditional casting and forging DC53 cold work die steel has better wear resistance.

Metoda sidetrackingu oparta na wykonaniu dwóch okien w kolumnach rur o różnych średnicach

While drilling from a vertical shaft the orientation of the diverter is carried out with the help of a magnetometer, leaving an interval of 18 m from the casing. The length of the milled interval could be reduced if a gyroscopic compass is used to orient the BHA. The open borehole section is covered with a strong cement sheath. To avoid magnetic interference, the bridge is drilled down to a depth of 6 m above the bottom of the open interval. A disadvantage of the full casing section milling method is an increased requirement on the strength of the cement bridge for drilling, and the difficulty in finding the head of the lower casing section if it needs to be drilled through after the sidetrack. In many cases, the mechanical drilling rate is limited by the conditions for removing cuttings, and for a horizontal section, the problem of removing cuttings becomes even more complicated. The design of modern milling tools is meant to produce small swarf that does not form clusters and is easily removed from the hole. During milling, it is preferable to flush the well with polymer drilling muds rather than clay muds. Hydrocarbon-based muds are not recommended for milling at all. An alternative to milling the entire casing cross-section is to make windows in the casing. This requires the installation of an oriented whipstock and the milling of the window in several stages. After a whipstock is positioned in the required direction, the stud connecting it with a milling machine of the first stage is cut off. On this basis, the paper proposes a method of sidetracking.

Electrical resistivity tomography (ERT) measurements during water flow in a date palm stem segment

Commercial cultivation of date palms has high economic significance, particularly in arid and hyper-arid regions. Achieving commercially viable yield of dates amid water scarcity and enforced restrictions on water use requires optimising the amount and timing of irrigation. To that end, better understanding of the temporal dynamics of the water use of date palm is of great importance. Traditionally, this can be achieved through sap flow estimates obtained using heat dissipation probes. However, such measurements lack the ability to provide information on the spatial distribution of sap flow, which is important considering that date palms transport water in the entire stem cross-section. The aim of this study is to evaluate whether electrical resistivity tomography measurements have the potential to provide information on the spatial variability of flow in date palm stems. For this, flow was induced through a stem segment that was obtained from a felled date palm tree. ERT measurements were continuously obtained throughout a cycle of flow and no-flow periods. The results showed that the mean bulk electrical conductivity varied strongly due to changes in the flow conditions. In addition, it was found that the electrical conductivity of the outflow was much higher than that of the inflow, which indicates the release of stored salt from the stem segment. Analysis of the spatial distribution of the electrical conductivity suggested that flow mainly occurred in a limited part of the cross-sectional area of the stem. Overall, it was concluded that the ERT is a promising tool to investigate the spatial variability of water flow in date palm stems.

Flame emission spectroscopy analysis of distributed liquid fuel combustion

Distributed combustion offers ultra-low pollutant emission, low susceptibility of thermoacoustic instabilities, and is highly fuel flexible, being an ideal choice for, e.g., boilers, furnaces, and gas turbines. It was recently demonstrated that Mixture Temperature-Control could also achieve distributed combustion and not restricted to Moderate or Intense, Low-oxygen Dilution combustion. The former approach is employed in the present paper. Online flame control is required by the need for dynamic operation, which is often performed via spectral flame measurements. Presently, the distribution of OH*, CH*, C2*, O2*, and two H2O* chemiluminescent emission peaks were evaluated; the first two represent ignition, while the latter four appear later in the reaction zone. Characteristics of distributed flames are compared to those of straight and V-shaped flames, which are well-known in the literature. The following observations were made. Distributed combustion is lifted and occupies the entire cross-section of the combustion chamber without featuring a characteristic shape. The OH*/CH* ratio shows a low dependence on the equivalence ratio, and the reactions start only 50 mm downstream of the burner lip. The dominant radical was CH* for all distributed flames. As the equivalence ratio increases, the reaction zone moves slightly upstream.

Assessing Enhanced Acoustic Absorption From Sonosensitive Perfluorocarbon Emulsion With Magnetic Resonance-Guided High-Intensity Focused Ultrasound and a Percolated Tissue-Mimicking Flow Phantom.

Sonosensitive high-boiling point perfluorocarbon F8TAC18-PFOB emulsions previously exhibited thermal enhancement during focused ultrasound heating in ex vivo pig livers, kidneys and a laminar flow phantom. The main objectives of this study were to evaluate heating under turbulent conditions, observe perfusion effects, quantify heating in terms of acoustic absorption and model the experimental data. In this study, similar perfluorocarbon emulsions were circulated at incremental concentrations of 0.07, 0.13, 0.19 and 0.25% v:v through a percolated turbulent flow phantom, more representative of the biological tissue than a laminar flow phantom. The concentrations represent the droplet content in only the perfused fluid, rather than the droplet concentration throughout the entire cross-section. The temperature was measured with magnetic resonance thermometry, during focused ultrasound sonications of 67 W, 95% duty cycle and 33 s duration. These were used in Bioheat equation simulations to investigate in silico the thermal phenomena. The temperature change was compared with the control condition by circulating de-gassed and de-ionized water through the flow phantom without droplets. With these 1.24 µm diameter droplets at 0.25% v:v, the acoustic absorption coefficient increased from 0.93 ± 0.05 at 0.0% v:v to 1.82 ± 0.22 m-1 at 0.25% v:v using a 0.1 mL s-1 flow rate. Without perfusion at 0.25% v:v, an increase was observed from 1.23 ± 0.07 m-1 at 0.0% v:v to 1.65 ± 0.17 m-1. The results further support previously reported thermal enhancement with F8TAC18-PFOB emulsion, quantified the increased absorption at small concentration intervals, illustrated that the effects can be observed in a variety of visceral tissue models and provided a method to simulate untested scenarios.

Evaluation of reinforcement distribution of Al6061/TiC composites by computed tomography

In this study, Al6061/TiC (4-8-12 wt%) composites were produced by hot pressing method. Composites were analyzed along the entire cross-section with a computer-assisted tomography device (Micro-CT). It was determined that the TiC distribution was appropriate in all reinforcement ratios. Porosity values were determined both experimentally and by Micro-CT and finally the results were compared. An increase in porosity values was detected with increasing reinforcement ratio in the composites, and both experimental and Micro-CT based results were founded as consistent.

Opto-mechanical fiber sensing with optical and acoustic cladding modes

Optical fibers are an excellent sensor platform. However, the detection and analysis of media outside the cladding and coating of standard fibers represent a long-standing challenge: light that is guided in the single optical core mode does not reach these media. Cladding modes help work around this difficulty, as their transverse profiles span the entire cross-section of the fiber cladding and reach its outer boundary. In this tutorial, we introduce and discuss in detail two recent advances in optical fiber sensors that make use of cladding modes. Both concepts share optomechanics as a common underlying theme. First, we describe a spatially continuous distributed analysis using the optical cladding modes of the fiber. Light is coupled to these modes using Brillouin dynamic gratings, which are index perturbations associated with acoustic waves in the core that are stimulated by light. Unlike permanent gratings, which are routinely used to couple light with cladding modes, Brillouin dynamic gratings may be switched on and off at will and can be confined to short fiber sections at arbitrary locations in a random-access manner. Second, we present the extension of the cladding mode sensor concept to include acoustic rather than optical modes. The acoustic cladding modes may be stimulated and monitored by guided light in the single core mode, and their linewidths are modified by the elastic properties of surrounding media. The principles and analyses of both concepts are provided in detail, alongside examples of experimental setups and results.

Coastal acoustic tomography system for monitoring transect suspended sediment discharge of Yangtze river

Suspended sediment discharge (SSD) in the Yangtze River (YR) plays a crucial role in transporting nutrients and sediment to the YR estuaries and the East China Sea. In order to gather information on suspended sediment concentration (SSC) and SSD across an entire river cross-section, we investigated a novel method supported by Coastal Acoustic Tomography (CAT). Consequently, two CAT systems were employed to estimate the cross-section averaged SSC and SSD at the Datong (DT) station of the YR over approximately 2.5 years. Low (0.02 kg/m3), high (0.44 kg/m3), and mean (0.10 kg/m3) SSC values were successfully estimated. The SSD was primarily driven by water discharge, exhibiting low values (204 kg/s) during the dry season and a maximum of 36,299 kg/s during flood events, with the mean value of 3,903 kg/s throughout the observation period. The water sample and CAT results demonstrated high consistency, with correlation coefficients (R2) of 0.92 for SSC between the water sample and CAT results, and 0.96 for SSD between the DT result and CAT results. This study established the ability to monitor transect SSC and SSD in the YR using the CAT sound attenuation approach, offering the advantage of continuous real-time monitoring of transect river flow, SSC, and SSD, even during extreme flood events. For the success of this method, factors such as particle size, sound frequency selection, and the measurable distance between instruments must be meticulously considered. This work highlights the potential of CAT for monitoring riverine transect SSC and SSD.

Novel Focused Ion Beam Liftouts for Spatial Characterization of Spherical Biominerals With Transmission Electron Microscopy.

Focused ion beam (FIB) is frequently used to prepare electron- and X-ray-beam-transparent thin sections of samples, called lamellae. Typically, lamellae are prepared from only a subregion of a sample. In this paper, we present a novel approach for FIB lamella preparation of microscopic samples, wherein the entire cross-section of the whole sample can be investigated. The approach was demonstrated using spherical, porous, and often hollow microprecipitates of biologically precipitated calcium carbonate. The microprecipitate morphology made these biogenic samples more fragile and challenging than materials commonly investigated using FIB lamellae. Our method enables the appropriate orientation of the lamellae required for further electron/X-ray analyses after attachment to the transmission electron microscopy (TEM) grid post and facilitates more secure adhesion onto the grid post. We present evidence of autofluorescence in bacterially precipitated vaterite using this lamella preparation method coupled with TEM selected area diffraction. This innovative approach allows studying biomineralization at the micro to nano scales, which can provide novel insights into bacterial responses to microenvironmental conditions.

Evolution of the structure, texture and mechanical properties of a cold-swaged austenitic stainless steel during post-deformation annealing

In this work, we studied the effect of annealing temperature on the structure and texture, as well as the mechanical properties of the austenitic stainless steel AISI 316. Initially, the program material was subjected to cold rotary swaging with a reduction of 95%. Studies showed the formation of the structure and texture gradient during preliminary plastic deformation. Annealing at low temperatures (500-600°C) provoked polygonization, while the intensity of the and texture components remained unchanged. After annealing at 700°С, the onset of recrystallization was observed only in the subsurface layers of the rod. As a result of annealing at 800–900°C, static recrystallization occurred over the entire cross section of the rod, which caused dissipation of the texture gradient. Annealing at temperatures of 400–600°C was accompanied by an increase in the strength and hardness characteristics. Meanwhile, ductility also increased with the annealing temperature. Annealing at 700°C resulted in softening of the program material almost to the level of the initial cold-swaged state and a significant increase in ductility up to 16%.