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This paper proposes a new discrete‐time formulation of state‐space model for voltage source inverter (VSI) fed AC motors, introducing the free evolution of the motor state and characterized by both the simplification of torque and flux output equations and the definition of a predictive reference frame oriented on the rotor free evolution vector. The potential of the proposed model for high dynamics discrete‐time controller synthesis is illustrated through an application to SM‐PMSM.

A direct power control (DPC) of the doubly-fed induction generator (DFIG) is presented. A new method, which is based on the rotation of the space sector, clockwise or vice versa, is proposed to improve the performance of the switching table. Then, it is combined with a fuzzy system to have advantages of both rotation sector and fuzzy controller. The paper aims to discuss these issues.

In this paper, a new DPC of the DFIG is presented. To improve the performance of the switching table, a new method is proposed. The method is based on the rotation of the space sector, clockwise or vice versa. The excellence of the proposed method is proven. Then, it is shown that the performance of the system can be enhanced by using a fuzzy logic controller. The rotation method is combined with a fuzzy system.

Simulation shows that although sector rotation and fuzzy controller can improve the performance of the DFIG, a combination of both demonstrates a smoother response in order that reactive and active power ripples and THD of the injected current decrease in different speeds. Also, it is demonstrated that the proposed method is robust against parameters variations. However, a hardware experiment should be performed to be practically verified.

A sector rotation is proposed and its effect on the performance of the DFIG is considered. A simple method to write rules table is presented and the performance of sector rotation and fuzzy controller on the DFIG is analysed.

Considering the need for standard and cost-effective housing delivery in South Africa, this study aims to make a case for three-dimensional (3D) printing in housing delivery through an assessment of the inherent benefits and the factors that could acts as barriers to its adoption.

The study used a survey of construction professionals currently actively involved in a construction project in the country. Analysis of data gathered was done using a four-step analysis approach and relevant descriptive and inferential statistics were adopted.

The study revealed through factor analysis that 3D printing in housing delivery promises better cost delivery, increased productivity and stakeholder satisfaction, socio-economic benefits, improved quality and faster housing delivery. While these benefits exist, factors such as technical and operational issues of the 3D printing itself, organizational and personnel issues as well as lack of awareness of the inherent benefits and understanding of the technology among stakeholders can prove to be barriers to the adoption of the technology.

In the quest to achieve standard and affordable housing which is part of its National Development Plan 2030, the government can adopt 3D printing which promises significant benefits in terms of cost, time, quality, productivity and stakeholders’ satisfaction. Property developers can also adopt the technology to improve their housing delivery, competitive advantage and the economic value of their properties.

The study contributes significantly to the body of knowledge as it reveals the benefits and barriers of adopting 3D printing in housing delivery in South Africa – an aspect that has not gained significant attention in the fourth industrial revolution and housing delivery discuss in the country.

The purpose of this paper is to present a novel methodology to produce a large boat hull with a foam additive manufacturing (FAM) process. To respond to shipping market needs, this new process is being developed. FAM technology is a conventional three-dimensional (3D) printing process whereby layers are deposited onto a high-pressure head mounted on a six-axis robotic arm. Traditionally, molds and masters are made with computer numerical control (CNC) machining or finished by hand. Handcrafting the molds is obviously time-consuming and labor-intensive, but even CNC machining can be challenging for parts with complex geometries and tight deadlines.

The proposed FAM technology focuses on the masters and molds, that are directly produced by 3D printing. This paper describes an additive manufacturing technology through which the operator can create a large part and its tools using the capacities of this new FAM technology.

The study shows a comparison carried out between the traditional manufacturing process and the additive manufacturing process, which is illustrated through an industrial case of application in the manufacturing industry. This work details the application of FAM technology to fabricate a 2.5 m boat hull mold and the results show the time and cost savings of FAM in the fabrication of large molds.

Finally, the advantages and drawbacks of the FAM technology are then discussed and novel features such as monitoring system and control to improve the accuracy of partly printed are highlighted.

The following list is a first attempt to catalogue and describe systematically the British Museum's extensive holdings of early opera librettos and related plays. The great importance of these unpretentious booklets as supplementary and, more often than not, even primary sources for the history and bibliography of dramatic music, besides or instead of the scores, was already clearly recognized in the eighteenth century by Dr. Burney and other scholars. But it is only since 1914, the year in which O. G. T. Sonneck's Library of Congress Catalogue of opera librettos printed before 1800 appeared, that their documentary value could to any greater extent be put to general use in international musicological research. A similar bibliography of the British Museum librettos, while naturally duplicating many Washington entries, would produce a great number of additional tides, not a few of them otherwise unrecorded; it would provide the musical scholar with the key to a collection unequalled elsewhere in Europe, which owing to the peculiar nature of the material is not easily accessible by means of the General Catalogue.

Reports on the MSc group design project of students at the College of Aeronautics, Cranfield University. Details the design of the aircraft systems and their reliability and maintainability.

The use of organic materials in the construction of aircraft transparencies is introduced by discussing their properties in relation to the requirements of strength and vision of the different types of transparency in the variety of environmental conditions in which they have to operate. The advantages and disadvantages of the particular currently manufactured materials are examined and the way in which their individual properties may best be utilized in the design and construction of transparencies is described and demonstrated by showing examples of proven designs. Present and future developments of both rigid sheet and flexible interlayer materials are discussed, particular reference being made to the development of ‘high temperature’ materials and the use of plastic main plies in combination with glass face plies to form hard‐wearing lightweight laminates. With the present availabilty of the improved acrylic materials, the author looks forward to the possibility of a reduction in the required design factors and a change in the interpretation of the fail‐safe requirements enabling simpler, lighter windows using organic materials to be designed in the future.

The paper seeks to bridge the already familiar benefits of 3D printing (3DP) to the rehabilitation of cultural heritage, still based on the use of complex and expensive handcrafted techniques and scarce materials.

A compilation of different information on frequent anomalies in cultural heritage buildings and commonly used materials is conducted; subsequently, some innovative techniques used in the construction sector (3DP and 3D scanning) are addressed, as well as some case studies related to the rehabilitation of cultural heritage building elements, leading to a reflection on the opportunities and challenges of this application within these types of buildings.

The compilation of information summarised in the paper provided a clear reflection on the great potential of 3DP for cultural heritage rehabilitation, requiring the development of new mixtures (lime mortars, for example) compatible with the existing surface and, eventually, incorporating some residues that may improve interesting properties; the design of different extruders, compatible with the new mixtures developed and the articulation of 3D printers with the available mapping tools (photogrammetry and laser scanning) to reproduce the component as accurately as possible.

This paper sets the path for a new application of 3DP in construction, namely in the field of cultural heritage rehabilitation, by identifying some key opportunities, challenges and for designing the process flow associated with the different technologies involved.

This study aims on a broad review of Concrete's Rheological Properties. The Concrete is a commonly used engineering material because of its exquisite mechanical interpretation, but the addition of constituent amounts has significant effects on the concrete’s fresh properties. The workability of the concrete mixture is a short-term property, but it is anticipated to affect the concrete’s long-term property.

In this review, the concrete and workability definition; concrete’s rheology models like Bingham model, thixotropy model, H-B model and modified Bingham model; obtained rheological parameters of concrete; the effect of constituent’s rheological properties, which includes cement and aggregates; and the concrete’s rheological properties such as consistency, mobility, compatibility, workability and stability were studied in detail.

Also, this review study has detailed the constituents and concrete’s rheological properties effects. Moreover, it exhibits the relationship between yield stress and plastic viscosity in concrete’s rheological behavior. Hence, several methods have been reviewed, and performance has been noted. In that, the abrasion resistance concrete has attained the maximum compressive strength of 73.6 Mpa; the thixotropy approach has gained the lowest plastic viscosity at 22 Pa.s; and the model coaxial cylinder has recorded the lowest stress rate at 8 Pa.

This paper especially describes the possible strategies to constrain improper prediction of concrete’s rheological properties that make the workability and rheological behavior prediction simpler and more accurate. From this, future guidelines can afford for prediction of concrete rheological behavior by implementing novel enhancing numerical techniques and exploring the finest process to evaluate the workability.

In recent years, 3D printing technologies have been widely used in the construction industry. 3D printing in construction is very attractive because of its capability of process automation and the possibility of saving labor, waste materials, construction time and hazardous procedures for humans. Significant researches were conducted to identify the performance of the materials, while some researches focused on the development of novel techniques and methods, such as building information modeling. This paper aims to provide a detailed overview of the state-of-the-art of currently used 3D printing technologies in the construction areas and global acceptance in its applications.

The working principle of additive manufacturing in construction engineering (CE) is presented in terms of structural design, materials used and theoretical background of the leading technologies that are used to construct buildings and structures as well as their distinctive features.

The trends of 3D printing processes in CE are very promising, as well as the development of novel materials, will gain further momentum. The findings also indicate that the digital twin (DT) in construction technology would bring the industry a step forward toward achieving the goal of Industry 5.0.

This review highlights the prospects of digital manufacturing and the DT in construction engineering. It also indicates the future research direction of 3D printing in various constriction sectors.