Application of response surface method in the separation of radioactive material: a review

Response Surface Method (RSM) is one of the most popular and powerful tools for experimental design and optimization. This paper first reviewed the research progress of RSM in the separation and recovery of various radioactive materials, and verified the application of RSM in adsorption isotherm analysis and thermodynamic calculation. The main advantage of RSM in radioactive material separation is the reduction in the number of experiments required, resulting in considerably less radioactive material consumption, secondary waste generation, workload and radiation dose, which is valuable for the research of radioactive material separation.

Mathematical modeling of contact interaction of two electroelastic half-spaces (without electrode coating of surfaces) in the presence of a hard disk-like inclusion between them and pressure in the area of separation

Based on the use of a rigorous mathematical model that takes into account the connectivity of force and electric fields in electroelastic bodies, the contact interaction of two piezoelectric transversely isotropic half-spaces with different properties under compression (in the presence of a hard disk-shaped inclusion between them and pressure in the material separation region) was studied. The solution to the problem is obtained by representing the general solution of the static equations of the electroelasticity for a transversely isotropic body in terms of harmonic functions, followed by the construction of the boundary value problem of the electroelasticity to the consideration of the integral equation and the expansion of the desired function in a small parameter. As a special case from the constructed analytical expressions, the main parameters of the contact for two elastic transversely isotropic and isotropic half-spaces (with the inclusion between them and pressure in the separation region) are implied. Numerical results were obtained. The influence was studied of the electroelastic properties of half-spaces, the geometric dimensions of the inclusion, and loads on the parameters of the contact interaction of electroelastic bodies.

Application of Functional Magnetic Nanoparticles for Separation of Target Materials: A Review

: Magnetic nanoparticles (MNPs) have unique properties which have made them widely applicable in medicine and biology. Due to their responsiveness to external magnetic force, they are easy to work with. Functionalization of nanoparticles(NPs) effectively improves performance, increases stability in the body and acidic environment, and prevents the agglomeration of the particles. One of the important applications of these NPs is in the separation of materials as solid-phase extracting agents. On the other hand, functionalizing these NPs can increase the efficiency, stability, specificity, and sensitivity of the structure to separate the target. In this paper, various material separation studies have been collected and classified into several main groups based on material types. Study groups included functional MNPs for separating pathogen, organic and inorganic substances of environmental resources, removal of heavy metal ions, separation of biomolecules, isolation of cells, especially tumor cells, harvesting the microalgae. The results showed that this method has advantages such as high sensitivity and specificity, ease of use without needing an operator, requiring low costs, and is a time-saving technique not requiring sample preparation and concentration.

A semi-Lagrangian reproducing kernel particle method with particle-based shock algorithm for explosive welding simulation

The explosive welding process is an extreme-deformation problem that involves shock waves, large plastic deformation, and fragmentation around the collision point, which are extremely challenging features to model for the traditional mesh-based methods. In this work, a particle-based Godunov shock algorithm under a semi-Lagrangian reproducing kernel particle method (SL-RKPM) is introduced into the volumetric strain energy to accurately embed the key shock physics in the absence of a mesh or grid, which is shown to also ensure the conservation of linear momentum. For kernel stability, a deformation-dependent anisotropic kernel support update algorithm is proposed, which is shown to capture excessive plastic flow and material separation. A quasi-conforming nodal integration is adopted to avoid the need of updating conforming cells which is tedious in extreme deformations. It is shown that the proposed formulation effectively captures shocks, jet formation, and smooth-to-wavy interface morphology transition with good agreement with experimental results.

Methodology for Evaluating Risk of Visual Inspection Tasks of Aircraft Engine Blades

Risk assessment methods are widely used in aviation, but have not been demonstrated for visual inspection of aircraft engine components. The complexity in this field arises from the variety of defect types and the different manifestation thereof with each level of disassembly. A new risk framework was designed to include contextual factors. Those factors were identified using Bowtie analysis to be criticality, severity, and detectability. This framework yields a risk metric that describes the extent to which a defect might stay undetected during the inspection task, and result in adverse safety outcomes. A simplification of the framework provides a method for go/no-go decision-making. The results of the study reveal that the defect detectability is highly dependent on specific views of the blade, and the risk can be quantified. Defects that involve material separation or removal such as scratches, tip rub, nicks, tears, cracks, and breaking, are best shown in airfoil views. Defects that involve material deformation and change of shape, such as tip curl, dents on the leading edges, bents, and battered blades, have lower risk if edge views can be provided. This research proposes that many risk assessments may be reduced to three factors: consequence, likelihood, and a cofactor. The latter represents the industrial context, and can comprise multiple sub-factors that are application-specific. A method has been devised, including appropriate scales, for the inclusion of these into the risk assessment.

A method for three-dimensional modelling of the shear-clinching process

Three-dimensional modelling enables to determine the in-plane material flow in asymmetrical situation. Thus, the distortion of the sheets to be joined can be characterized more exactly. This study shows a method for building up a three-dimensional shear-clinching framework without damage criteria. In fact, the die-sided sheet in shear-clinching was designed as a pre-punched sheet and slugs. The material separation in the die-sided joining partner, which in two-dimensional simulation is often described by macro- and micromechanical fracture criteria, was realised in this study based on a defined contact condition. By means of a shear-cutting simulation, a correlation between the break angle and the separation stress was determined, which was used as a separation criterion in the shear-clinching simulation. The separation line was confirmed using post-particles. To validate this model, the results of the simulation using a quadratic single-point specimen were compared to the experiments with respect to the distortion of the joining partner. In general, the built three-dimensional framework provides for further tool developments with regard to the reduction of distortion in shear-clinching.

FUINDAMENTALS DEVELOPMENT FOR COMPUTATION OF SCREW SCREENS FOR BULK MATERIAL SEPARATION AND EXPERIENCE OF THEIR INTRODUCTION TO PRODUCTION

The work purpose is to increase productivity in bulk material separation by means of the development of a test sample of the installation for bulk material separation into fractions. There is considered bulk material motion in a working chamber of the screw screen and the results of experimental investigations of bulk medium movement parameters are presented, depending on design and operation characteristics of screw screens, and also nomograms of dependences of a rate of bulk particle longitudinal movements upon a screw screen diameter, for different values of correction factors, weight of bulk particles, an angular velocity of the screw screen and fill factors. A design of the plant for bulk separation, test data and technical characteristics of the test plant are shown. A novelty is confirmed by six invention patents of the RF. By means of the complex method of investigations there are obtained dependences for definition of a rate of bulk particle longitudinal motion in screw screens, and also a length of working chamber of the screw screen.

Improving design and application method of screening bucket excavators

The purpose of the study is to increase the productivity and economic efficiency of mining operations using screening bucket excavators on the basis of the introduction of a new technical and technological solution that expands equipment functionality. The study involves the analysis of known designs of screening buckets installed on excavators that ensure material separation to be carried out simultaneously with excavation and loading works. It is noted that a promising development direction of screening buckets is a design with working drums. The article presents an excavator with a modernized screening bucket and its operation technology, which allows to start rock mass sorting in the bucket while the excavator is turning to the place of unloading. The improved screening bucket is equipped with a hinged movable bottom controlled by hydraulic cylinders to accumulate fine fractions screened through the working drums. Fine fractions accumulated in the moving bottom are unloaded into a dump truck, after which screening continues directly into the body of the dump truck. Screening finished, the movable bottom closes and the excavator unloads the coarse fractions remaining in the bucket into another vehicle. Unloading is carried out by bucket turning. The combination of screening and excavator turning reduces the operation cycle time, which increases the performance of both the excavator and dump trucks. The use of a modernized screening bucket with a moving bottom eliminates the loss of valuable fine material as a result of spilling when the excavator turns for unloading. The movable bottom can be installed on the screening buckets of known designs and does not require their significant alteration. Application of the proposed technical and technological solution will reduce unit costs and increase the efficiency of work.

The Frictional Force between Slug and Die in Shear Cutting after Material Separation

Frictional forces in sheet metal blanking are central in different aspects, e.g. in wear prediction, validation of simulation models or in so called slug pulling. The latter is a phenomenon where the slug is pulled out of the die by the punch after the sheet metal is separated. This leads to process disturbances reaching from a blocked belt feeder up to severe tool damage caused by the simultaneous cutting of the slug and the sheet metal strip. A sufficiently high frictional force between the slug and the die prevents this effect. Despite its importance, this force and its causes have not yet been investigated in detail. A method was developed in this paper to measure the frictional force between slug and die. A shear cutting tool with an integrated piezoelectric load cell and an inductive position sensor was used on a stamping press to cut sheet metal made of CuSn6 (R350, thickness 1 mm). The die clearance, the punch edge radii and the lubrication conditions were varied. A larger die clearance resulted in a lower frictional force while a larger punch edge radius increased it significantly. Lubrication reduced the frictional force, especially for small die clearances. Finally, the cause of the frictional force was investigated by identifying the relevant springback modes of the slugs. This was carried out by correlating the slugs' deflection, oversize, and clean cut height with the frictional force. Especially the slug oversize, i.e. the difference between the slug's diameter and the die's inner diameter, revealed a strong correlation. Calculations showed that the deformation in radial direction is the main cause of the frictional force between slug and die. It suggests that the slug oversize is a good measure for the magnitude of the frictional force.