Excessive Distortion Research Articles

A Dual‐Insertion Type Sodium‐Ion Full Cell Based on High‐Quality Ternary‐Metal Prussian Blue Analogs

AbstractPrussian blue analogs (PBAs) are especially investigated as superior cathodes for sodium‐ion batteries (SIBs) due to high theoretical capacity (≈170 mA h g−1) with 2‐Na storage and low cost. However, PBAs suffer poor cyclability due to irreversible phase transition in deep charge/discharge states. PBAs also suffer low crystallinity, with considerable [Fe(CN)6] vacancies, and coordinated water in crystal frameworks. Presently, a new chelating agent/surfactant coassisted crystallization method is developed to prepare high‐quality (HQ) ternary‐metal NixCo1−x[Fe(CN)6] PBAs. By introducing inactive metal Ni to suppress capacity fading caused by excessive lattice distortion, these PBAs have tunable limits on depth of charge/discharge. HQ‐NixCo1−x[Fe(CN)6] (x = 0.3) demonstrates the best reversible Na‐storage behavior with a specific capacity of ≈145 mA h g−1 and a remarkably improved cycle performance, with ≈90% capacity retention over 600 cycles at 5 C. Furthermore, a dual‐insertion full cell on the cathode and NaTi2(PO4)3 anode delivers reversible capacity of ≈110 mA h g−1 at a current rate of 1.0 C without capacity fading over 300 cycles, showing promise as a high‐performance SIB for large‐scale energy‐storage systems. The ultrastable cyclability achieved in the lab and explained herein is far beyond that of any previously reported PBA‐based full cells.

Controlling Angular Distortion in Manual Metal Arc Welding of Austenitic Stainless Steels Using Back-step Technique

Nowadays, austenitic stainless steels (A.S.S.) have many industrial applications in the fields of chemical and petrochemical processing, marine, medicine, water treatment, petroleum refining, food and drinks processing, nuclear power generation etc. The secret behind this wide range of applications is the fact that A.S.S. have great corrosion resistance, high strength and scale resistance at elevated temperatures, good ductility at low temperatures approached to absolute zero in addition to notable weldability. On the other hand, manual metal arc (MMA) is probably the most common process used for the welding of A.S.S. Unfortunately, MMA welding of A.S.S. could be associated with considerable distortion. Uncontrolled or excessive distortion usually increases the cost of the production process due to the high expense of rectification or replacing the weldment by a non-distorted one.
 MMA welding of A.S.S. was carried out using the back-step technique with various bead lengths, and without using this technique for comparison.
 Results have showed that the angular distortion was a function of the bead length in the back-step welding of A.S.S. The angular distortion decreased by (14.32%) when the back-step technique was used with a (60 mm) length for each bead, and by (41.08%) when the bead length was (40 mm). On the other hand, it increased by (25%) when the back-step technique was done with a (30 mm) length for each bead.

Наглядность изображений в техническом рисунке

This publication is devoted to the definition of one of the graphics forms – technical drawing, its conventions, clarity, possible lack of visibility, and means of addressing them. The concept of "technical drawing" is defined ambiguously by different authors in different textbooks. Very often it is implied that technical drawing is an image of technical parts, components, and similar products. Sometimes the word "technical" means "auxiliary", "helping" to express this or that design (architectural or constructive) idea. Tutorials for technical drawing (engineering graphics, engineering drawing) the technical drawing in most cases is considered as a drawing according to perspective rules– as a special kind of axonometric drawing. Because in the drawing courses are studied mainly the so-called standard axonometric projection, some authors believe that technical drawings shall be either isometric or dimetric (rectangular or oblique). Advanced technical drawings usually are not mentioned in textbooks on engineering graphics, and information about them is missing. There is no analysis of the characteristics that distinguish the "visual image" from the "not visual" one. Technical drawing is an object’s illustrative graphical representation made by hand or other means, in visual scale, correctly disclosing a technical idea, object design. "Visibility" of the image should be connected with the completeness of the information that this image gives to the viewer. A visual representation should approximately correspond to the visual image of the object when looking at it in space, in nature, to avoid excessive distortions of the surface and design. The perspective images transfuse an impression of objects’ outside appearance and create the effect of "viewer presence" close to the depicted object. But as construction of the perspective image is more labor intensive than of the axonometric one, and shape distortions in perspective are more significant, so visual images are often performed according to axonometric rules. Unacceptable distortions of objects visual image on the images in oblique projections limit the possibilities of their application.

Characterization of phenolic pellets for ESR dosimetry in photon beam radiotherapy.

This work deals with the dosimetric features of a particular phenolic compound (IRGANOX 1076®) for dosimetry of clinical photon beams by using electron spin resonance (ESR) spectroscopy. After the optimization of the ESR readout parameters (namely modulation amplitude and microwave power) to maximise the signal without excessive spectrum distortions, basic dosimetric properties of laboratory-made phenolic dosimeters in pellet form, such as reproducibility, dose-response, sensitivity, linearity and dose rate dependence were investigated. The dosimeters were tested by measuring the depth dose profile of a 6MV photon beam. A satisfactory intra-batch reproducibility of the ESR signal of the manufactured dosimeters was obtained. The ESR signal proved to increase linearly with increasing dose in the investigated dose range 1-13Gy. The presence of an intrinsic background signal limits the minimum detectable dose to a value of approximately 0.6Gy. Reliable and accurate assessment of the dose was achieved, independently of the dose rate. Such characteristics, together with the fact that IRGANOX 1076® is almost tissue-equivalent, and the stability of the ESR signal, make these dosimeters promising materials for ESR dosimetric applications in radiotherapy.

Directional cell expansion requires NIMA-related kinase 6 (NEK6)-mediated cortical microtubule destabilization

Plant cortical microtubules align perpendicular to the growth axis to determine the direction of cell growth. However, it remains unclear how plant cells form well-organized cortical microtubule arrays in the absence of a centrosome. In this study, we investigated the functions of Arabidopsis NIMA-related kinase 6 (NEK6), which regulates microtubule organization during anisotropic cell expansion. Quantitative analysis of hypocotyl cell growth in the nek6-1 mutant demonstrated that NEK6 suppresses ectopic outgrowth and promotes cell elongation in different regions of the hypocotyl. Loss of NEK6 function led to excessive microtubule waving and distortion, implying that NEK6 suppresses the aberrant cortical microtubules. Live cell imaging showed that NEK6 localizes to the microtubule lattice and to the shrinking plus and minus ends of microtubules. In agreement with this observation, the induced overexpression of NEK6 reduced and disorganized cortical microtubules and suppressed cell elongation. Furthermore, we identified five phosphorylation sites in β-tubulin that serve as substrates for NEK6 in vitro. Alanine substitution of the phosphorylation site Thr166 promoted incorporation of mutant β-tubulin into microtubules. Taken together, these results suggest that NEK6 promotes directional cell growth through phosphorylation of β-tubulin and the resulting destabilization of cortical microtubules.

Depiction of interfacial morphology in impact welded Ti/Cu bimetallic systems using smoothed particle hydrodynamics

Numerical simulations of high-velocity impact welding are extremely challenging due to the coupled physics and highly dynamic nature of the process. Thus, conventional mesh-based numerical methodologies are not able to accurately model the process owing to the excessive mesh distortion close to the interface of two welded materials. A simulation platform was developed using smoothed particle hydrodynamics, implemented in a parallel architecture on a supercomputer. Then, the numerical simulations were compared to experimental tests conducted by vaporizing foil actuator welding. The close correspondence of the experiment and modeling in terms of interface characteristics allows the prediction of local temperature and strain distributions, which are not easily measured.

Angular momentum of dark matter black holes

The putative black holes which may constitute all the dark matter are described by a Kerr metric with only two parameters, mass M and angular momentum J. There has been little discussion of J since it plays no role in the upcoming attempt at detection by microlensing. Nevertheless J does play a central role in understanding the previous lack of detection, especially of CMB distortion. We explain why bounds previously derived from lack of CMB distortion are too strong for primordial black holes with J non-vanishing. Almost none of the dark matter black holes can be from stellar collapse, and nearly all are primordial, to avoid excessive CMB distortion.

Transient distortion behavior during TIG welding of thin steel plate

To examine the generation characteristics of excessive distortions involved with the welding-induced buckling of a thin steel plate, the temperature profiles and distortion behaviors of welded plates during tungsten inert gas (TIG) welding were experimentally measured. Large-deformation thermal elastic–plastic analysis based on arc physics-based heat source modeling was utilized to accurately simulate the thermomechanical behavior of the plate during welding. The calculated and measured temperature profiles and distortion behaviors were compared to validate the developed numerical analysis technique. On the basis of the developed analysis technique, the effect of geometric imperfections on the thermomechanical behavior of welded thin steel plates was further investigated. Both angular and longitudinal bending distortions were found to monotonically increase with increasing heat input because of excessive longitudinal bending distortion and the secondary generation of angular distortion during the cooling process when buckling occurred. The through-thickness gradient of the plastic strain that developed with the transient distortion behavior during welding resulted in excessive angular distortion in the welded thin steel plate. It was concluded that the transient distortion behavior during welding should be taken into consideration to accurately predict and control large welding-induced distortions in thin steel plates.

The study of under- and over-sampling methods’ utility in analysis of highly imbalanced data on osteoporosis

Osteoporosis is a frequent bone disease without typical early symptoms but with serious complications e.g. low-energy bone fractures. Patients with risk factors should be screened for proper diagnosis as early as possible. Unfortunately, the registered medical data are often highly imbalanced. That is why the machine-based data processing is difficult or even impossible. Considering this, our goal was to search for the best method of coping with the problem of imbalancing in relation to the analysed data regarding the osteoporotic patients. Therefore, we checked several paradigms of classifiers in synergy with preprocessing techniques to address the inner skewed class distribution of the data.In the source dataset 92.6% of instances related to patients without any fractures (negative cases) and only 7.41% to patients (positive cases) who reported at least one fracture. To alleviate class imbalance there were examined not only data-level methods which in fact modify the input dataset, but also ensemble ones that strengthen the results of the base algorithms. In the first group the under- and over-sampling methods were used, such as random undersampling, edited nearest neighbours and synthetic minority over-sampling techniques, while in the second one – a range of methods based on various subsets of training data were analysed. Also various combinations of the above mentioned were investigated. Additionally, we propose the way how to find the balancing level which, without excessive distortion of the input, raw data, will give the appropriate classification efficiency.The aim of our experiment was to identify which of an undersampling or an oversampling approach with reference to the simple and the ensemble-based classifiers allows to achieve the best results.The outcomes of the comparative studies concerning imbalancing problem with regard to our dataset showed that the highest efficiency was achieved while using the synthetic minority over-sampling technique and RandomForest classifier. As far as the optimal balancing level is concerned, we empirically determined that 300% oversampling with the synthetic minority over-sampling method combined with edited nearest neighbours undersampling allowed to gain the required precision of classification.

Numerical Investigations of the Effect of Process Parameters on Residual Stresses, Strains and Quality of Final Product in Blanking Using SPH Method

The shearing process such as the blanking of sheet metals has been used often to prepare workpieces for subsequent forming operations. This process consists in separating a blank from a sheet by means of a high-localized shear deformation due to the action of a punch. Blanking modelling is becoming an increasingly important tool in gaining understanding and improving this process. At the moment a fundamental problem in numerical modelling of blanking processes is an excessive element distortion in a finite-element simulation. In this study, we present a hybrid modelling approach, SPH (smoothed particle hydrodynamics) coupled FEM method to simulate the blanking process. This new approach involves several advantages compared to the traditional finite element method for example: neglect mesh tangling and distortion problems, does not need to use material separation criterion. The physical, mathematical and computer model of the process is elaborated. The application in ANSYS/LS-DYNA program is developed. The examination and analysis of influence of process technological parameters for example: the clearance, tool geometry, blanking velocity on residual stresses, strains and quality of final product using the SPH method is analyzed. The results of computer simulations can be used to forecasting quality of the parts optimization.

Numerical studies on high-velocity impact welding: smoothed particle hydrodynamics (SPH) and arbitrary Lagrangian–Eulerian (ALE)

The manufacturing industry often relies on numerical simulations to reduce the number of trial-and-error iterations required during the process development to reduce costs. However, this can be difficult in high strain rate manufacturing processes. For instance, in high-velocity impact welding, extremely high plastic strain regions develop. Thus, a traditional pure Lagrangian analysis is not able to accurately model the process due to excessive element distortion near the contact zone. In this paper, numerical simulations were conducted using smoothed particle hydrodynamics (SPH) and arbitrary Lagrangian–Eulerian (ALE) methods to investigate a high-velocity oblique impact between two metal plates. While the preliminary results show that the two methods were capable of modeling the process, a trade-off between the computational cost and full prediction of the critical process parameters should be considered for industrial applications.

Assessment of finite element and smoothed particles hydrodynamics methods for modeling serrated chip formation in hardened steel

This study aims to perform comparative analyses in modeling serrated chip morphologies using traditional finite element and smoothed particles hydrodynamics methods. Although finite element models are being employed in predicting machining performance variables for the last two decades, many drawbacks and limitations exist with the current finite element models. The problems like excessive mesh distortions, high numerical cost of adaptive meshing techniques, and need of geometric chip separation criteria hinder its practical implementation in metal cutting industries. In this study, a mesh free method, namely, smoothed particles hydrodynamics, is implemented for modeling serrated chip morphology while machining AISI H13 hardened tool steel. The smoothed particles hydrodynamics models are compared with the traditional finite element models, and it has been found that the smoothed particles hydrodynamics models have good capabilities in handling large distortions and do not need any geometric or mesh-based chip separation criterion.

Cold sprayed copper coating: numerical study of particle impact and coating characterization

Cold spraying technique is a promising process fabricating high quality metallic coatings. This work concerns both numerical and experimental investigations of cold sprayed copper coating taking into account impact conditions including, particle velocities and temperature, gas pressure and material nature. The conducted numerical study is an examination of the deformation behavior of Cu particles sprayed onto steel substrate using Abaqus/explicit software, allowing a good understanding of the deposition characteristics of copper particles and the effect of particle velocity on the coating microstructure. The numerical results show that particle impact velocity has a significant effect on its morphology; Lagrangian method exhibits an excessive distortion of the elements in the case of high impact velocity and fine meshing size, whereas simulation of particle impact using arbitrary Lagrangian-Eulerian (ALE) method is close to the experimental observations.

Bearing and Cleavage Failure Simulation of Single Lap Bolted Joint Using Finite Element Method

This paper deals with the distortion and failure behavior of the single lap bolted joints with similar and dissimilar substrates experimentally and numerically. Nonlinear finite element (FE) model has been used to simulate excessive distortions and failure modes of the assemblies. FE results show that elasto-plastic model has sufficient accuracy in predicting the distortion behavior of the models with only bearing failure. However, this model has less accuracy compared to other models with Mixed-Mode (Bearing + Cleavage) failure. Therefore, in this paper, an energy based failure criteria has been used to simulate the joint distortions and rupture. Results show that the joint behavior can be accurately simulated using the above mentioned failure criterion.

Reconstruction of lateral defects of the tip and supratip less than 1.5 cm in diameter

The authors describe the surgical technique as well as the indications and limitations of the East-West flap for repair of lateral defects of the tip/supratip of the nose less than 1.5cm in diameter. This easy and reliable technique is based on the use of skin from the lower third of the nose to repair the defect. This tissue presents the same thickness and colour characteristics, which limits excessive thickness, distortion and dyschromia phenomena.

Low Distortion Solvent Bonding of Microfluidic Chips

Solvent bonding represents a joining method for thermoplastic materials that results in high bond strength, with short process times. However, there is a challenge in bonding micro-channeled substrates for microfluidic devices due to excessive channel clogging and distortion. In this work, a simple design method to fuse poly(methyl methacrylate) microfluidic chips with solvents without micro-channel clogging is demonstrated. The joining process is improvised improved by subjecting the chip to a vacuum during the bonding process, whereby the undesired excess solvent between the microfluidic chip and cover can be removed. The microfluidic devices that were bonded using this method exceeded the application requirements, in particular transparency and internal back pressure requirements.

Oil Field Retrofit of ESPs to Meet Harmonic Compliance

A large petrochemical company installed nearly 50 000 hp of electrical submersible pumps (ESPs) at an existing midwest U.S. oil field. Being equipped with adjustable-speed drives (ASDs), these ESPs introduced high levels of current harmonic distortion, which resulted in 14%–19% voltage harmonic distortion at the electrical utility supply. Initially, the utility noticed the low power factor (PF) and had the oil company pay for the installation of power factor correction (PFC) capacitors on their medium-voltage supply. Once installed, the utility began to have problems with these capacitors and continued to receive complaints from other customers adjacent to the oil field; thus, they enforced harmonic limits, as defined by IEEE Std 519, at all points of common coupling. Measurements were made with a harmonic analyzer at several locations throughout the electrical system to quantify harmonics and determine the effect the ESPs were having on the utility distribution system. Computer simulations were performed to analyze different methods of harmonic mitigation. Ultimately, passive harmonic filters were installed on all ESPs in phases. In addition, the PFC capacitors were permanently disconnected after determining that a power system resonance condition existed. Once all phases of the project were complete, the voltage distortion level decreased to below 5%, and PF improved to near unity without the PFC capacitors. This paper will describe the effect of harmonics on the electrical distribution system caused by ASDs, practical solutions to excessive voltage harmonic distortion, resonance issues with PFC capacitors, and the challenges associated with different methods of harmonic mitigation.

Computational analysis of inter-material mixing and weld-flaw formation during dissimilar-filler-metal friction stir welding (FSW)

Purpose – Friction stir welding (FSW) butt-joining involving the use of a dissimilar filler metal insert between the retreating and advancing portions of the workpiece is investigated computationally using a combined Eulerian-Lagrangian (CEL) finite element analysis (FEA). The emphasis of the computational analysis was placed on the understanding of the inter-material mixing and weld-flaw formation during a dissimilar-material FSW process. The paper aims to discuss these issues. Design/methodology/approach – The FEA employed is of a two-way thermo-mechanical character (i.e. frictional-sliding/plastic-work dissipation was taken to act as a heat source in the energy conservation equation), while temperature is allowed to affect mechanical aspects of the model through temperature-dependent material properties. Within the analysis, the workpiece and the filler-metal insert are treated as different materials within the Eulerian subdomain, while the tool was treated as a conventional Lagrangian subdomain. The use of the CEL formulation within the workpiece insert helped avoid numerical difficulties associated with excessive Lagrangian element distortion. Findings – The results obtained revealed that, in order to obtain flaw-free FSW joints with properly mixed filler and base materials, process parameters including the location of the tool relative to the centerline of the weld must be selected judiciously. Originality/value – To the authors’ knowledge, the present work is the first reported attempt to simulate FSW of dissimilar materials.

Arbitrary Lagrangian–Eulerian finite element simulation and experimental investigation of wavy interfacial morphology during high velocity impact welding

Finite element simulations of high strain rate forming processes are of significant interest to industry, but are challenging due to the coupled physics and dynamic nature of the processes. For instance, in high velocity impact welding, extremely high plastic strain regions develop. Thus, a traditional pure Lagrangian analysis is not able to accurately model the process due to excessive element distortion near the contact zone. In this study, the Arbitrary Lagrangian–Eulerian method (ALE) was used to simulate an impact welding process for two Al6061-T6 plates. The ALE method was able to numerically predict the temperature at the interface as well as the necessary process parameters to achieve a wavy morphology at the interface of the materials which is assumed to be a characteristic of a quality impact weld. This allowed the prediction of a weldability window, including separate regions for melting and purely solid state welds. To validate the proposed numerical model and wavy morphology regions, experimental tests with a Vaporizing Foil Actuator Welding (VFAW) process were conducted including Photon Doppler Velocimetry (PDV) measurements of the impact velocity. The numerical results were in good agreement with the experimental tests including the temperature prediction and interfacial melting observed through microstructural analyses.

Restoration of images degraded by underwater turbulence using structure tensor oriented image quality (STOIQ) metric.

Recent advances in image processing for atmospheric propagation have provided a foundation for tackling the similar but perhaps more complex problem of underwater imaging, which is impaired by scattering and optical turbulence. As a result of these impairments underwater imagery suffers from excessive noise, blur, and distortion. Underwater turbulence impact on light propagation becomes critical at longer distances as well as near thermocline and mixing layers. In this work, we demonstrate a method for restoration of underwater images that are severely degraded by underwater turbulence. The key element of the approach is derivation of a structure tensor oriented image quality metric, which is subsequently incorporated into a lucky patch image processing framework. The utility of the proposed image quality measure guided by local edge strength and orientation is emphasized by comparing the restoration results to an unsuccessful restoration obtained with equivalent processing utilizing a standard isotropic metric. Advantages of the proposed approach versus three other state-of-the-art image restoration techniques are demonstrated using the data obtained in the laboratory water tank and in a natural environment underwater experiment. Quantitative comparison of the restoration results is performed via structural similarity index measure and normalized mutual information metric.