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As manufacturing technology has developed, digital models from advanced measuring devices have been widely used in manufacturing sectors. To speed up the production cycle and reduce extra errors introduced in surface reconstruction processes, directly machining digital models in the polygonal stereolithographyformat has been considered as an effective approach in rapid digital manufacturing. In machining processes, Cutter Location (CL) data for numerical control (NC) machining is generated usually from an offset model. This model is created by offsetting each vertex of the original model along its vertex vector. However, this method has the drawback of overcut to the offset model. The purpose of this paper is to solve the overcut problem through an error compensation algorithm to the vertex offset model.

Based on the analysis of the vertex offset method and the offset model generated, the authors developed and implemented an error compensation method to correct the offset models and generated the accurate CL data for the subsequent machining process. This error compensation method is verified through three polygonal models and the tool paths generated were used for a real part machining.

Based on the analysis of the vertex offset method and the offset model generated, the authors developed an error compensation method to correct the offset models and generated the accurate CL data for the subsequent machining process. The developed error compensation algorithm can effectively solve the overcut drawback of the vertex offset method.

The error compensation method to the vertex offset model is used for generating the CL data with the using of a ball-end cutter.

On the study of CL data generation for a STL model, most of the current studies are focused on the determination of the offset vectors of the vertexes. The offset distance is usually fixed to the radius of the cutter used. Thus, the overcut problem to the offset model is inevitable and has not been much studied. The authors propose an effective approach to compensate the insufficient distance of the offset vertex and solve the overcut problem.

The directly tool paths generation from a STL model can reduce the error of surface reconstruction and speed up the machining progress.

The authors investigate the overcut problem occurred in vertex offset for CL data generation and present a new error compensation algorithm for generating the CL data that can effectively solve the overcut problem.

Remanufacturing of worn blades with various defects normally requires processes such as scanning, regenerating a geometrical reference model, additive manufacturing (AM) through laser cladding, adaptive machining and polishing and quality inspection. Unlike the manufacturing process of a new part, the most difficult problem for remanufacturing such a complex surface part is that the reference model adaptive to the worn part is no longer available or useful. The worn parts may suffer from geometrical deformation, distortion and other defects because of the effects of harsh operating conditions, thereby making their original computer aided design (CAD) models inadequate for the repair process. This paper aims to regenerate the geometric models for the worn parts, which is a key issue for implementing AM to build up the parts and adaptive machining to reform the parts. Unlike straight blades with similar cross sections, the tip geometry of the worn tip of a twist blade needs to be regenerated by a different method.

This paper proposes a surface extension algorithm for the reconstruction of a twist blade tip through the extremum parameterization of a B-spline basis function. Based on the cross sections of the scanned worn blade model, the given control points and knot vectors are firstly reconstructed into a B-spline curve D. After the extremum of each control point is calculated by extremum parameterization of a B-spline basis function, the unknown control points are calculated by substituting the extremum into the curve D. Once all control points are determined, the B-spline surface of the worn blade tip can be regenerated. Finally, the extension algorithm is implemented and validated with several examples.

The proposed algorithm was implemented and verified through the exampled blades. Through the extension algorithm, the tip geometry of the worn tip of a twist blade can be regenerated. This method solved a key problem for the repair of a twist blade tip. It provides an appropriate reference model for repairing worn blade tips through AM to build up the blade tip and adaptive machining/polishing processes to reform the blade geometry.

The extension errors for different repair models are compared and analyzed. The authors found that there are several factors affecting the accuracy of the regenerated model. When the cross-section interval and the extension length are set properly, the restoration accuracy for the blade tip can be improved, which is acceptable for the repairing.

The lack of a reference geometric model for worn blades is a significant problem when implementing blade repair through AM and adaptive machining processes. Because the geometric reference model is unavailable for the repair process, reconstruction of the geometry of a worn blade tip is the first crucial step. The authors proposed a surface extension algorithm for the reconstruction of a twist blade tip. Through the implementation of the proposed algorithm, the blade tip model can be regenerated.

Remanufacturing of worn blades with various defects is highly demeaned for the aerospace enterprises considering sustainable development. Unlike straight blades, repair of twist blades encountered a very difficult problem because the geometric reference model is unavailable for the repair processes. This paper proposed a different method to generate the reference model for the repair of a twist blade tip. With this model, repair of twist blades can be implemented through AM to build up the blade tip and adaptive machining to subtract the extra material.

The authors proposed a surface extension algorithm to reconstruct the geometric model for repair of twist blades.

The purpose of this study is to solve the key problem of the residual stress of strip in buckling and deviation during the continuous annealing process (CAP).

Considering the one-to-one correspondence between deformation and residual stress, the strip was divided into multiple elements. To obtain the total deformation of each element, the influence model of some factors on the deformation of steel strip element was established. Then, according to the constitutive equation of residual stress and deformation, and the deformation coordination relation between strip elements, a set of calculation model, which is suitable for residual stress of strip during CAP was established, the model precision was verified by finite element method simulation, and the influences on residual stress of strip were also analyzed.

The weighted calculation of comparison between analytical results and simulation shows that the accuracy of the analytical method is within 10 per cent, which fully meets the requirements.

The different residual stress of steel strip can be displayed quickly and intuitively in the synchronous process segment according to this model, which is of great importance to the prevention of strip buckling and deviation.

Through the tracer fiber method, we strive to more accurately obtain the hook degree, straightening degree, percentage and other characteristic indexes. In order to intuitively represent the hook state from sliver to yarn, and feed back production information in combination with quality test.

Taking the cotton fiber as an example, the hooked fibers were studied by using the tracer fiber method. Tracer fibers were made from cotton-type viscose fibers. Tracer fibers and combed cotton fibers were uniformly mixed for many times and used to produce the card sliver, semi-drawn sliver, drawn sliver, roving and yarn. With the help of ZF-20D ultraviolet analyzer, geometric parameters of hooked fibers were measured, and characterization indexes were calculated. And hook indexes and quality indexes were compared.

By redefining and reclassifying hooked fibers, the change of hooked fibers in the process was tracked and characterized carefully. Some hooks in card sliver are straightened but not eliminated, and will form longer zero-angled hooks in the subsequent process. The straightening degree and number of zero-angled hooks affect the evenness CV mainly.

The characterization of hooked fibers is important for reducing hooked fibers and spinning high quality yarns. There is no uniform standard for the characterization of hooked fibers at present. Most studies are about relationship between process and hook in carding and drawing. There is no research on hooked fibers in the whole spinning process. In the paper, hooked fibers were redefined and reclassified, the change of hooked fibers in the process was tracked and characterized carefully.

This study aims to fabricate and manipulate ensemble spin of negative nitrogen-vacancy (NV⁻) centres optimally for future solid atomic magnetometers/gyroscope. Parameters for sample preparation most related to magnetometers/gyroscope are, in particular, the concentration and homogeneity of the NV⁻ centres, the parameters’ microwave antenna of resonance frequency and the strength of the microwave on NV⁻ centres. Besides, the abundance of other impurities such as neutral NV centres (NV⁰) and substitutional nitrogen in the lattice also plays a critical role in magnetic sensing.

The authors succeeded in fabricating the assembly of NV centres in diamond and they determined its concentration of (2-3) × 10¹⁶ cm⁻³ with irradiation followed by annealing under a high temperature condition. They explored a novel magnetic resonance approach to detect the weak magnetic fields that takes advantage of the solid-state electron ensemble spin of NV⁻ centres in diamond. In particular, the authors set up a magnetic sensor on the basis of the assembly of NV centres. They succeeded in fabricating the assembly of NV centres in diamond and determined its concentration. They also clarified the magnetic field intensity measured at different positions along the antenna with different lengths, and they found the optimal position where the signal of the magnetic field reaches the maximum.

The authors mainly reported preparation, initialization, manipulation and measurement of the ensemble spin of the NV centres in diamond using optical excitation and microwave radiation methods with variation of the external magnetic field. They determined the optimal parameters of irradiation and annealing to generate the ensemble NV centres, and a concentration of NV⁻ centres as high as 10¹⁶ cm⁻³ in diamond was obtained. In addition, they found that sensitivity of the magnetometer using this method can reach as low as 5.22 µT/Hz currently.

This research can shed light on the development of an atomic magnetometer and a gyroscope on the basis of the ensemble spin of NV centres in diamond.

High concentration spin of NV⁻ in diamond is one of the advantages compared with that of the atomic vapor cells, because it can obtain a higher concentration. When increasing the spin concentration, the spin signal is easy to detect, and macro-atomic spin magnetometer become possible. This research is the first step for solid atomic magnetometers with high spin density and high sensitivity potentially with further optimization. It has a wide range of applications from fundamental physics tests, sensor applications and navigation to detection of NMR signals.

As has been pointed out, in this research, the authors mainly worked on fabricating NV⁻ centres with high concentration (10¹⁵-10¹⁶ cm⁻³) in diamond by using optimal irradiation and annealing processes, and they quantitatively defined the NV⁻ concentration, which is important for the design of higher concentration processes in the magnetometer and gyroscope. Until now, few groups can directly define the NV⁻ concentration. Besides, the authors optimized the microwave antenna parameters experimentally and explored the dependence between the splitting of the magnetic resonance and the magnetic fields, which dictated the minimum detectable magnetic field.

The purpose of this study is to assess the impact of Covid-19 on sustainable fashion consumption behavior by proposing a conceptual framework combining consumer-specific factors and product-specific factors with a special emphasis on consumer value perceptions.

Theory of consumption value was integrated into the knowledge, attitude behavior model in the conceptual framework having consumer-specific and product-specific aspects. Perceived value (PERVAL) scale was used to measure value perceptions. The model was verified by a survey conducted among a random sample of 520 participants. The factors were extracted by using exploratory factor analysis and then confirmed by using confirmatory factor analysis. The hypotheses in the conceptual model were tested for different consumer groups, and the strength of the relationships was calculated by using multigroup analysis in structural equation modeling.

It was observed the environmental concern raised the need for getting knowledge about the environment. The impact of environmental knowledge on the value perception of sustainable fashion products varied for the consumers affected by Covid-19 at different levels. Quality perception and price perception were influenced most by environmental knowledge in that order for the consumers with “high fear and uncertainty” and “low fear and uncertainty”. Similarly, the perceived emotional and social values were influential on purchase intention for consumers with high fear and uncertainty, whereas price and social value perceptions were influential for the consumers with low fear and uncertainty.

This study is the initial study that investigated the impact of the Covid-19 pandemic on the consumption of sustainable fashion products. The integration of theory of consumption value into the knowledge, attitude behavior model allowed identifying the relationship between environmental issues and sustainable fashion consumption. Using the PERVAL scale for measuring perceived value, the study provided valuable insights for understanding the most important value dimensions for sustainable fashion products for consumer groups affected by Covid-19 at different levels. The results regarding the changes in the rankings related to the impact of environmental knowledge on dimensions of perceived value and the impact of perceived values on purchase intention enabled the integrated model to explain the attitude–behavior gap.

This paper aims to establish the wideband model of a sub-module in a modular multilevel converter (MMC) and analyze the switch transients of the sub-module.

The paper builds an MMC sub-module test circuit and conducts dynamic tests both with and without the bypass thyristor. Then, it builds the wideband model of the MMC sub-module and extracts the model parameters. Finally, based on the wideband model, it simulates the switch transients and analyzes the oscillation mechanism.

The dynamic testing shows the bypass thyristor will add oscillations during switch transients, especially during the turn-on process. The thyristor acts like a small capacitor and reduces the total capacitor in the turn-on circuit loop, thus causing under-damped oscillations.

This paper found that the bypass thyristor will influence the MMC sub-module switch transients under certain circumstances. This paper proposes a partial inductance extraction procedure for the MMC sub-module and builds a wideband model of the sub-module. The wideband model is used to analyze and explain the switch transients, and can be further used for insulated gate bipolar transistor switch oscillation inhibition and sub-module design optimization.

The aim of the paper is to provide an economically viable solution for the blade repair process. There is a continual increase in the repair market, which requires an increased level of specialised technology to reduce the repair cost and to increase productivity of the process.Design/methodology/approach – This paper introduces the aerospace component defects to be repaired. Current repair technologies including building‐up and machining technology are reviewed. Through the analysis of these available technologies, this paper proposes an integrated repair strategy through information integration and processes concentration.Findings – Provides detailed description and discussion for the repair system, including 3D digitising system, repair inspection, reverse engineering‐based polygonal modelling, and adaptive laser cladding and adaptive machining process.Originality/value – This paper describes a 3D non‐contact measurement‐based repair integration system, and provides a solution to create an individual blade‐oriented nominal model to achieve adaptive repair process (laser cladding/machining) and automated inspection.

The purpose of this paper is to expound the concept of the coordinated development of the transport system, and provide a quantitative method to support decision making in urban transportation development planning.

To analyze the organic composition of urban transport system, research the meaning and mechanism of coordinated development of transport system. On the basis of researching relations of transport and external systems and its subsystems, to research quantitative theoretical model of the coordinated development and assessment of the transport system.

Establishing models needs to analyze the coordination among the various indices of subsystem, calculate the overall coordination between indices of the subsystem and all the indices of other subsystems, then inspect the coordinated development among subsystems.

How to design the indexes of the subsystem of urban transport system is the main limitation.

Offering theoretical foundation for coordinated development of urban transport system.

Putting forward quantitative theoretical model on coordinated development of urban transport system, which lays a foundation for further study.

This paper discusses research on machining and repairing of turbomachinery components which are generally complex geometries and made up of difficult to machine materials (nickel super alloys or titanium alloys).

The approaches, methods and methodologies used for machining and repairing of blades are reviewed as well as the comparisons between them are made.

Particularly, the most recent blade machining and repair techniques using high flexible machine tools and industrial robots, are mentioned.

The limitation of the approaches, methods and methodologies are given and supported by real practical application examples.

This paper presents a state of the art review of research in machining and repairing of turbomachinery components, which have been mainly done in the last decade. The paper act as a reference, gathering the works about turbomachinery components from a manufacturing point of view.