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The electrical properties of piezoelectric vibrators have a crucial influence on the operating state of ultrasonic motors. In order to solve the problem that the current piezoelectric vibrator generates a large amount of heat during vibration to degrade its performance, which in turn affects the normal operation of ultrasonic motors, this paper prepares a novel piezoelectric vibrator and tests its maximum vibration velocity under the working condition, which is more than twice as much as that of the current commercial PZT-8.

The crystal structures of the samples were analyzed by using an X-ray diffractometer. For microstructure observation, samples were observed by scanning electron microscope (SEM). The quasi-static piezoelectric coefficient meter (ZJ-3AN) was used for piezoelectric measurement. Dielectric properties were measured by utilizing an impedance analyzer (Agilent 4294A) with a laboratory heating unit. Ferroelectric hysteresis loops were obtained using a ferroelectric analyzer (Radiant, Multiferroic 100). A Doppler laser vibrometer (Polytec PSV-300F, Germany) and a power amplifier were used for piezoelectric vibration measurements, during which the temperature rise was determined by an infrared radiation thermometer (Victor 303, China).

The ceramics exhibit enhanced piezoelectric performance at 0.1–0.4 mol% of Yb doping contents. The ceramic of 0.4 mol% Yb reaches the maximal internal bias field and presents a larger mechanical quality factor of 1,692 compared with that of 0.2 mol% Yb-doped ceramic, in spite of a slightly decreased dielectric constant of 439 pC/N, the unit of the piezoelectric constant, which is the ratio of the local charge (pC) to the frontal force (N) and electromechanical coupling coefficient of 0.63. The vibrator with this large mechanical quality factor ceramic displays a vibration velocity of up to 0.81 m/s under the constraint of 20 °C temperature rising, which is much higher than commercial high-power piezoelectric ceramics PZT-8.

The enhanced high-power properties of the piezoelectric vibrator by Yb doping may provide a potential application for the high-performance USM and offer the possibility of long-term stable operation under high power for special equipment like USM. In the subsequent phase of research, the novel PZT-based high-power piezoelectric vibrator can be utilized in the USM, and the motor's performance will be evaluated under aerospace conditions to objectively assess the reliability of the piezoelectric vibrator.

In this chapter, the author examines the way in which the purchase and delivery infrastructure of darknet cryptomarkets shapes the experience of opiate drug use and dependence. It uses the concept of social time and posits that the illicit drug distribution system reshapes two temporal dimensions shaping the experience of drug users. There is the experience of time located in the pharmacology of the drug and in the body of the drug user, which evokes experiences of withdrawal and dependence. Then there is the socio-technical embedding of the delivery system and governance structures which support or impinge on the autonomy of the user. This ‘drug time’ is both a benefit and a cost of engaging in cryptomarket use. The market infrastructure can give users the opportunities to more carefully manage their drug time, while also creating new risks of non-delivery that can sharpen experiences of dope sickness. The author concludes that the growing professionalisation, digitisation, and commercialisation of the drug market increasingly embed drug time in material infrastructures mediated through technical systems.

The purpose of this study is to verify how the carbon doping of the WC-Co cemented carbide (CC) affected their structure before their processing by hot isostatic pressing (HIP) technology.

The samples for this experiment were fabricated by selective laser melting technology (SLM) using a YAG fiber laser with a power of P = 40 W and a scanning speed of 83 mm/s. The subsequent carbon doping process was performed in a chamber furnace at 900 0 C for 1, 4 and 12 h. The HIP was performed at 1,390°C and pressures of 40 MPa, 80 MPa and 120 MPa. The changes induced in the structures were evaluated using X-ray diffraction and various microscopic methods.

X-ray diffraction analysis showed that the structure of the samples after SLM consisted of WC, W₂C, Co₄W₂C and Co phases. As a result of the increase in the carbon content in the structure of the samples, the transition carbide W₂C and structural phase Co₄W₂C decayed. Their decay was manifested by the coarsening of the minor alpha phase (WC), which occurred both during the carburizing process and during the subsequent processing using HIP. In the samples in which the structure was carburized prior to HIP, only the structural phases WC and Co were observed in most cases.

The results confirm that it is possible to increase the homogeneity of the CC structure and thus its applicability in practice by additional carburization of the sample structure with subsequent processing by HIP technology.

In this study, AlCoCrFeNi–Cu (Cu-based) and AlCoCrFeNi–Ti (Ti-based) high entropy alloys (HEAs) were fabricated using a direct blown powder technique via laser additive manufacturing on an A301 steel baseplate for aerospace applications. The purpose of this research is to investigate the electrical resistivity and oxidation behavior of the as-built copper (Cu)- and titanium (Ti)-based alloys and to understand the alloying effect, the HEAs core effects and the influence of laser parameters on the physical properties of the alloys.

The as-received AlCoCrFeNiCu and AlCoCrFeNiTi powders were used to fabricate HEA clads on an A301 steel baseplate preheated at 400°C using a 3 kW Rofin Sinar dY044 continuous-wave laser-deposition system fitted with a KUKA robotic arm. The deposits were sectioned using an electric cutting machine and prepared by standard metallographic methods to investigate the electrical and oxidation properties of the alloys.

The results showed that the laser power had the most influence on the physical properties of the alloys. The Ti-based alloy had better resistivity than the Cu-based alloy, whereas the Cu-based alloy had better oxidation residence than the Ti-based alloy which attributed to the compositional alloying effect (Cu, aluminum and nickel) and the orderliness of the lattice, which is significantly associated with the electron transportation; consequently, the more distorted the lattice, the easier the transportation of electrons and the better the properties of the HEAs.

It is evident from the studies that the composition of HEAs and the laser processing parameters are two significant factors that influence the physical properties of laser deposited HEAs for aerospace applications.

This conceptual paper proposes an intellectual capital (IC) framework dedicated to elite athletes (EA) to demonstrate the usefulness of IC on individual persons. Thus, it connects EA with the concept of IC.

The paper is inspired by the classical IC dimensions (human capital, structural capital and relational capital), which are used to develop the IC framework for EA. An exemplary case study is used to validate the framework.

It is argued that there is a need to adapt the traditional IC framework for EA. Therefore, this paper proposes a specific IC framework consisting of natural capital, sports capital and media capital.

This paper deals with EA and the sports industry, but should be extended to other sectors where aspects such as image and celebrity represent significant intangible resources.

The proposed IC framework can help EA and their managers to better understand how IC value is created.

This paper extends the IC concept to other fields of application, i.e. EA, and thus individual persons.

While the Olympic Games are always under the spotlight, the Paralympic Games are somehow ignored. This paper aims to invite the general public to think about the para-athletes and the differential treatments they received.

Among the participating countries, many of them were unable to win a single Olympic or Paralympic medal. When the dependent variable is left-censored, ordinary least squares regression is asymptotically biased downwards. In the literature, researchers typically employ the maximum likelihood Tobit model to take care of the censoring problem. However, some researchers argue that the Hurdle model has an advantage over the Tobit model in identifying the determinants of winning Olympic medals. Following their wisdom, this paper employs both the Tobit and Hurdle models in analysis.

The empirical evidence gathered in this paper suggests that population size, host status and average years of schooling are the big three socio-economic determinants when it comes to winning medals at the Paralympic Games and Olympic Games. The findings support the hypothesis that sports talent is randomly distributed and a large country has a higher chance to have talented athletes or para-athletes winning the Olympic medals. The strong host advantage also showed up in the following Paralympics but was not so strong at the next Olympics.

This paper not only examines the relationship between various social, economic and political factors in determining the success of a nation in the Paralympic Games but also attempts to identify possible non-traditional determinants.

The purpose of this paper is to identify if fraud theory models suggested over the years are applicable to match-fixing and if so, whether the Krambia-Kapardis’ (2016) holistic fraud and corruption prevention model can be used to reduce significantly match-fixing in football.

An online survey was developed by the authors and was administered to football stakeholders in Cyprus, namely, players, referees, coaches and team management.

The research questions, who are the initiators of match-fixing, why is match-fixing taking place and what is the best way to prevent or reduce match-fixing, have been answered, and these findings have enabled the authors to make policy recommendations.

The survey considered match-fixing in only one sport (football) while the number of respondent categories and the 335 usable questionnaires returned did not allow advanced statistical analysis of the data obtained.

The findings point to the need both for ethics and moral values to be installed in all the stakeholders through training and continuing education. It is also suggested that teams/clubs and related associations acting as regulators ought to implement governance principles and ethical programs, including whistleblowing lines and appoint integrity officers to minimize the match-fixing phenomenon. Furthermore, society, as well as government, sport regulators and sponsors, ought to encourage and demand fair play and integrity in sport through improved measures of governance and accountability and the implementation of ethical audits and public disclosure of audited financial statements of teams. Finally, sports integrity ought to be embedded in school curriculum from a very young age.

To the best of the authors’ knowledge, this is an original contribution to knowledge that has impact on the future of sporting fairness and social legitimacy.

The purpose of this paper is to explore the reasons for the discontinuation of sports sponsor–sponsee relationships and categorize them. Despite the negative outcomes of a sponsorship dissolution, research on this topic is rather scarce.

The paper relies on an analysis of 24 historical cases and 19 in-depth interviews focusing on the Dutch soccer league. Several sponsorship disruptors are identified and clustered into four categories.

The four categories for sponsorship dissolution are the following: sponsor-related factors, sponsee-related factors, inter-relational factors and external factors. In total, ten sponsorship disruptors are identified: insufficient value creation, objectives achieved, sports results, signal to society, exclusivity, negativity, personal relationship, changed marketing strategy, financial situation and legislation and regulation.

This study primarily investigates soccer sponsorship cases. Future research could investigate other sponsorship areas, which could yield different reasons for sponsorship termination.

Practitioners are advised to view the sponsorship relationship as a strategic alliance, rather than a resource, from the beginning of the sponsorship. A solid relational framework is needed, which is built around the elements of trust, commitment and collaborative communication. If such a foundation does not exist or has eroded, the sponsorship relationship is fragile and can be endangered by various factors.

This study uses inductive reasoning to devise a framework that enables sponsees to anticipate when sponsors are likely to discontinue their sponsorship such that the sponsees can take actions accordingly. Apart from validating existing reasons for sponsorship dissolution, this research also presents novel and previously undiscovered sponsorship disruptors.

While the main purpose of reporting – e.g. reporting for taxes – is to gauge the economic state of a company, the fact that reporting is done at pre-determined dates distorts the reporting results. For example, to create a larger impression of their productivity, companies fire temporary workers before the reporting date and re-hire then right away. The purpose of this study is to decide how to avoid such distortion.

This study aims to come up with a solution which is applicable for all possible reasonable optimality criteria. Thus, a general formalism for describing and analyzing all such criteria is used.

This study shows that most distortion problems will disappear if the fixed pre-determined reporting dates are replaced with individualized random reporting dates. This study also shows that for all reasonable optimality criteria, the optimal way to assign reporting dates is to do it uniformly.

This study shows that for all reasonable optimality criteria, the optimal way to assign reporting dates is to do it uniformly.

It is found that the individualized random tax reporting dates would be beneficial for economy.

It is found that the individualized random tax reporting dates would be beneficial for society as a whole.

This study proposes a new idea of replacing the fixed pre-determining reporting dates with randomized ones. On the informal level, this idea may have been proposed earlier, but what is completely new is our analysis of which randomization of reporting dates is the best for economy: it turns out that under all reasonable optimality criteria, uniform randomization works the best.