Methods of optimisation in machine design

The paper is devoted to the problem of optimal machine design selection by developing and solving the problem of multi-criteria optimisation, using the method suggesting a unified criterion with the use of weighting factors based on expert estimates. Based on the example of the design of a multi-purpose machine for service electric transport, a mathematical model of parametric optimisation of the design of electric and combined propulsion plants is developed. The most efficient system components are selected to meet the customer's requirements.

Enhancing the magnetocaloric response of high-entropy metallic-glass by microstructural control

Non-equiatomic high-entropy alloys (HEAs), the second-generation multi-phase HEAs, have been recently reported with outstanding properties that surpass the typical limits of conventional alloys and/or the first-generation equiatomic single-phase HEAs. For magnetocaloric HEAs, non-equiatomic (Gd36Tb20Co20Al24)100−xFex microwires, with Curie temperatures up to 108 K, overcome the typical low temperature limit of rare-earth-containing HEAs (which typically concentrate lower than around 60 K). For alloys with x = 2 and 3, they possess some nanocrystals, though very minor, which offers a widening in the Curie temperature distribution. In this work, we further optimize the magnetocaloric responses of x = 3 microwires by microstructural control using the current annealing technique. With this processing method, the precipitation of nanocrystals within the amorphous matrix leads to a phase compositional difference in the microwires. The multi-phase character leads to challenges in rescaling the magnetocaloric curves, which is overcome by using two reference temperatures during the scaling procedure. The phase composition difference increases with increasing current density, whereby within a certain range, the working temperature span broadens and simultaneously offers relative cooling power values that are at least 2-fold larger than many reported conventional magnetocaloric alloys, both single amorphous phase or multi-phase character (amorphous and nanocrystalline). Among the amorphous rare-earth-containing HEAs, our work increases the working temperature beyond the typical <60 K limit while maintaining a comparable magnetocaloric effect. This demonstrates that microstructural control is a feasible way, in addition to appropriate compositional design selection, to optimize the magnetocaloric effect of HEAs.

Design methodology of analytical games for knowledge acquisition

Analytical games explore a problem or a domain with a research purpose. Considerable research is ongoing to investigate improvements to analytical game design, execution and exploitation. Moreover, the fast-paced technological developments in many fields, such as artificial intelligence and virtual reality, make it even more compellingto account for the advantages and limitations of these new capabilities. In game design, the use of digital means is often regarded as a mere technical factor that relates to the platform selection, facilitator support and data recording processes. In this work a shift in perspective is proposed, to move from technology-oriented design selection criteria towards a broader assessment of the design choices. In fact, the introductionof technology (i.e., automation and autonomy) will not lead to a substitution of tasks, but will intrinsically change the game environment. This work introduces a framework to provide a structured guidance on the aspects to be factored in the different design phases of an analytical game, including the potential impact of the adoption of automation and autonomy. The proposed approach is based on previous research in the fieldof simulation-based serious gaming, model-driven engineering and human factors engineering. The framework is applied to Knowledge Acquisition Analytical Games as a case study.

A Comparative Analysis of Selection Criteria of Candidates in Belgium

The literature on candidate selection has focussed extensively on the degree of inclusiveness and decentralization of the selectorate, as part of the debate on intra-party democracy. However, much less attention has been paid to the degree of openness of candidacies, or selection criteria within parties. Yet parties have a lot of leeway in how they design selection criteria internally. Which guidelines do parties follow when making the crucial choice on which candidates to select for elections? This paper investigates selection criteria from two perspectives: the formal rules set by parties that restrict the candidate’s pool and the (informal) preferences of selectors that shape who gets selected. We aim first at contrasting the degree of party institutionalization and parties’ formal rules in candidate selection and so, we shed light on whether parties formalise their candidacy requirements and candidate selection processes to the same extent as other party activities. Second, the paper investigates the role of the selectorates, and how selectorate’s characteristics matter for the kind of (informal) selection criteria, be they intended at maximizing offices, votes or policies. Drawing on party statutes coded in the Political Party Database (PPDB) and 23 in-depth interviews with selectors, we study three francophone Belgian parties that differ both in terms of inclusiveness of the selectorate who has the final say on candidate selection and in terms of degree of centralisation, and in terms of party institutionalisation: the green party (Ecolo), the socialist party (PS), and the liberal party (MR). Our comparative analysis of parties, selection criteria provides new insights into the secret garden of politics and highlights in particular the major impact of parties, degree of centralization.

A Review on Process and Practices in Operation and Design Modification of Ejectors

This work reviews the current operational condition and activities on design modification for different applications of ejectors. Ejectors being a simple mechanical system capable of performing multiple fluid related functions (vacuum generation, pumping, mixing, condensing and heat exchanging), have been an essential part of several industrial processes. Two areas have been emphasized; internal flow and application-based modifications in components of ejectors. The geometry and inlet flow conditions were found to be the prime influencing factor of its performance. The objective and application-based modifications were performed on the primary nozzle, secondary nozzle, mixing chamber, throat and diffuser. The resultant performance was found to be dependent on operational condition and fluid type. This emphasizes the requirement of application-based design selection of the technology. In addition, the flow dynamics of condensing, non-condensing, particle and slurry flow has been studied based on available literatures. The one-point final objective is to identify the usability of primary water jet ejectors for active vapor transport and condensation, to replace vacuum pump and condenser in compact domestic water desalination system.

Clinical Trials

Clinical trials (a.k.a. clinical studies) in vaccinology are investigations with humans to assess the immunogenicity, reactogenicity i.e., the expected local or systemic symptoms of the desired immune response, safety and/or efficacy or effectiveness of vaccines. Such investigations must be designed, conducted, and analysed based on scientific principles to get sound answers to specific questions stated in the trial plan. Since Clinical Trials involve human subjects, highest ethical standards need to be applied. In addition, national laws, licensing regulations and international standards, for example Declaration of Helsinki, regulate the procedures and conduct of clinical trials. Vaccine trials can be classified by development phase (phase I-III before licensure; phase IV post-licensure); by purpose; or role of the investigator. The study protocol covers design, selection of study subjects, selection of endpoints, methods to minimize bias, conduct of the study and analysis plan, all aimed at answering the study question with best possible internal scientific validity.

Transient overvoltage characteristics in submarine cables of multi-terminal flexible HVDC transmission system

The overvoltage transient characteristics of submarine cables are one of the key technologies for submarine power transmission. This article takes the submarine cable of Zhoushan Multi-terminal Flexible HVDC Transmission Project as the research object. The MMC-HVDC simulation models at both ends of converter stations are built in PSCAD. The parameters and equivalent models of the flexible HVDC cables are determined, and the submarine DC cable operating overvoltage is calculated by using statistical methods. The simulation results show that the maximum overvoltage of the submarine cable, that is, the maximum overvoltage of the conductor to sheath, the sheath to the armour, and the armour to the ground are 400 kV, 7.27 kV and 0.45kV respectively. The maximum overvoltage when it occurs faults on grid-side or valve-side appears in the middle of the submarine cable. Maximum overvoltage of HVDC single pole grounding fault appears at the connection point of land cable and submarine cable. The simulation results and the discovery of features in this article provide reference in the design, selection, and testing of submarine power transmission equipment.