Comparative Safety Analysis of Accelerator Driven Subcritical Systems and Critical Nuclear Energy Systems

The accelerator driven subcritical system (ADS) has been chosen as one of the best candidates for Generation IV nuclear energy systems which could not only produce clean energy but also incinerate nuclear waste. The transient characteristics and operation principles of ADS are significantly different from those of the critical nuclear energy system (CNES). In this work, the safety characteristics of ADS are analyzed and compared with CNES by a developed neutronics and thermal-hydraulics coupled code named ARTAP. Three typical accidents are carried out in both ADS and CNES, including reactivity insertion, loss of flow, and loss of heat sink. The comparison results show that the power and the temperatures of fuel, cladding, and coolant of the CNES reactor are much higher than those of the ADS reactor during the reactivity insertion accident, which means ADS has a better safety advantage than CNES. However, due to the subcriticality of the ADS core and its low sensitivity to negative reactivity feedback, the simulation results indicate that the inherent safety characteristics of CNES are better than those of ADS under loss of flow accident, and the protection system of ADS would be quickly activated to achieve an emergency shutdown after the accident occurs. For the loss of heat sink, it is found that the peak temperatures of the cladding in the ADS and CNES reactors are lower than the safety limit, which imply these two reactors have good safety performance against loss of heat sink accidents

Between branding and being:how are inclusive city branding and inclusive city practices related?

Purpose: The purpose of this study is to investigate the relationship between being an inclusive city and branding oneself as such, as more cities adopt the inclusive city concept as part of their brand identity. Design/methodology/approach: This paper builds theory by introducing a typology that categorizes cities based on their level of inclusion and degree of branding, supplemented by an analysis of the branding practices and identities. Integrating the literature on inclusive city and city branding, with a specific focus on the inherent conflict between their sharing and competing attributes, this research postulates that a city may choose to engage in being inclusive and branding itself as such in various ways depending on its dominant motivations of altruism or entrepreneurialism. Findings: Four distinct types of inclusive city branding are identified: inclusion ambassadors (high inclusion and high branding); innate champions (high inclusion and low branding); façade marketers (low inclusion and high branding); and silent segregators (low inclusion and low branding). Furthermore, it underscores that inclusive city branding is shaped by the interplay of entrepreneurialism and altruism, not just a city’s inclusion. Different branding practices, such as media-generated images, narratives and events, are emphasized when entrepreneurialism is the primary motivation, whereas iconic architecture buildings, flagship projects and long-term policies are more associated with altruism. Originality/value: This study develops a typology to unravel the paradoxical aspects of inclusive city branding. Examining the intersection of city branding motivations and practices enriches existing literature. Moreover, its findings offer valuable insights for cities grappling with the implementation of contentious inclusive branding strategies, thereby bridging theory with practical applications.</p

Will the true inclusive city rise? Mapping the strengths and weaknesses of the city ranking systems

Ranking cities is considered an effective instrument to rate and qualify the specific image of cities and encourage them to define and improve sustainable development strategies, but it has also been criticized for generating biased outcomes. Recently, the number of rankings for inclusive cities is rising, in fact along with growing investments in inclusive city projects and initiatives. The inclusive city rankings have both the strength to enhance lesson-drawing and self-improvement and the weakness to exacerbate competition among un-equals. In this article, nine different ranking systems for assessing urban inclusion are scrutinized and compared. Based on relevant theory regarding inclusive urban development and ranking systems, a methodology to compare and assess ranking systems is established, building on different quality aspects. The findings indicate that although for most ranking systems much essential information to understand how they produce results can be retrieved, motivations for generating these inclusive city rankings can be moral, utilitarian, or a combination of both, and that evaluation methods and dissemination of the results sometimes lack transparency and timeliness. Some metrics are incomplete and/or biased toward specific dimensions and indicators. The consistency across the ranking systems in producing the best-performing cities is much stronger than that of the worst-performing cities. Moreover, an obvious developed-developing gap was observed in the sense that most high performers are in Europe and to a lesser extent Nord-America, while the bottom 25 % are primarily in developing countries. Finally, suggestions are given to make methodologies for inclusive ranking systems more transparent, comprehensive and less biased.</p

Investigate of the influence of pin deviation on the biomechanical environment of fixator-bone system by finite element method

Unilateral external fixators are widely used in orthopedics to stabilize fractured bones and in the treatment of limb deformities. Vivo mechanical environment inside and around the fixator may influence the healing of fractured bone. Due to the existence of pin deviation may affect biomechanical environment of callus in the fracture gap. Finite element analysis was used to investigating stress and deformation of fixator-bone system under axial load, torsional load and bending load, comparing the biomechanical properties of two fixator structures: the one has pin deviation angle, the other has no pin deviation angle. These results reveal that the existence of pin deviation would affect the biomechanical environment of fractured bone. When fixator-bone system under three kinds of load, the stress and deformation of fixator-bone system were greater than that of fixator-bone system without pin deviation. This work provides orthopedics doctor useful information to predict the micromovements of fixator-bone system