1,758 research outputs found

    B Decays in an Asymmetric Left-Right Model

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    Motivated by recently observed disagreements with the SM predictions in BB decays, we study bd,sb \to d, s transitions in an asymmetric class of SU(2)L×SU(2)R×U(1)BLSU(2)_L \times SU(2)_R \times U(1)_{B-L} models, with a simple one-parameter structure of the right handed mixing matrix for the quarks, which obeys the constraints from kaon physics. We use experimental constraints on the branching ratios of bsγb \to s \gamma, bceνˉeb \to c e {\bar \nu}_e, and Bd,s0Bˉd,s0B_{d,s}^0 -\bar{B}^0_{d,s} mixing to restrict the parameters of the model: gR/gL,MW2,MH±,tanβ\displaystyle {g_R}/{g_L}, M_{W_2}, M_{H^\pm}, \tan \beta as well as the elements of the right-handed quark mixing matrix VCKMRV^R_{CKM}. We present a comparison with the more commonly used (manifest) left-right symmetric model. Our analysis exposes the parameters most sensitive to bb transitions and reveals a large parameter space where left- and right-handed quarks mix differently, opening the possibility of observing marked differences in behaviour between the standard model and the left-right model.Comment: 32 pages and 8 figure

    Maintenance/repair and production-oriented life cycle cost/earning model for ship structural optimisation during conceptual design stage

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    The aim of this paper is to investigate the effect of the change in structural weight due to optimisation experiments on life cycle cost and earning elements using the life cycle cost/earning model, which was developed for structure optimisation. The relation between structural variables and relevant cost/earning elements are explored and discussed in detail. The developed model is restricted to the relevant life cycle cost and earning elements, namely production cost, periodic maintenance cost, fuel oil cost, operational earning and dismantling earning. Therefore it is important to emphasise here that the cost/earning figure calculated through the developed methodology will not be a full life cycle cost/earning value for a subject vessel, but will be the relevant life cycle cost/earning value. As one of the main focuses of this paper is the maintenance/repair issue, the data was collected from a number of ship operators and was solely used for the purpose of regression analysis. An illustrative example for a chemical tanker is provided to show the applicability of the proposed approac

    Emerging digital technologies and consumer decision-making in retail sector: towards an integrative conceptual framework

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    This paper explores the influence of digital technologies on the consumer decision-making in retail sector with two online survey-based studies. Study 1 identifies unique attributes of six digital technologies, including two current (Internet and Mobile Platform) and four emerging (Artificial Intelligence, Augmented, Mixed and Virtual Reality) technologies. Study two focuses on older consumers to understand their decision-making process when shopping for products or services using new digital technologies. We extend the AISAS (Awareness, Interest, Search, Action, and Sharing) model to show that with digital technologies, consumer decision journey is no longer linear. For example, attention can lead directly to action, without going through the interest or search stages. Similarly, purchase can lead to sharing that may lead to loyalty and psychological engagement, and reinforce attention. We found no significant difference in these effects between older and younger consumers. Besides providing useful insights about consumer decision-making process with emerging digital technologies for future academic researchers, these results also give useful ideas to marketing practitioners interested in introducing these emerging technologies to deliver superior value to their customers

    Investigating the roughness effect of biofouling on propeller performance

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    As a result of the increasing pressure being placed on the marine industry to address ship emissions, regulations to govern the fuel efficiency and efficient operation of ships in the form of the Energy Efficiency Design Index (EEDI) (IMO, 2014) and Energy Efficiency Operation Index (EEOI) (IMO, 2009a) have recently come into force. These have been introduced alongside regulations concerning specific emissions requirements (UNFCCC). Attention has therefore been turned to all aspects of ship design and operation which have impact on their efficiency. In turn, this paper focuses on the effects of biofouling on propeller surfaces highlighting the benefits of reducing biofouling. This subject was the focus of a recently completed EU-Funded FP7 Project entitled FOUL-X-SPEL (2011). This paper investigates the detrimental impacts of biofouling on the performance of a real ship propeller using Computational Fluid Dynamics (CFD) simulations. Initially, the CFD approach used in this study was validated through CFD open-water tests of a propeller. A previously-developed CFD approach for approximating the surface roughness that results from biofouling has then been applied in order to predict the effects on propeller efficiency. The roughness effects of a typical coating and different fouling conditions on the propeller performance were therefore predicted for various advance coefficients Results indicated negative effects of biofouling on the propeller efficiency and the importance of the mitigation of such effects, supporting the importance of informing the industry about the impacts such that they are able to make informed decisions regarding regular propeller maintenance and cleanin

    Corporate identity management: a study of employees’ perceptions in the context of the retail and the hospitality and tourism sectors

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    This research delves into the evolving landscape of corporate identity and its interplay with corporate reputation. To construct a relevant corporate identity scale, we relied on the existing literature and conducted comprehensive interviews with personnel in the hospitality and tourism, and retail sectors. We then gathered survey responses from 690 individuals in hospitality and tourism, and 649 in retail, to evaluate the corporate identity scale's dimensions and its link to corporate reputation. Our findings validate the proposed model, highlighting that corporate reputation is significantly shaped by various facets of corporate identity. Notably, empowerment directly influences corporate reputation, while elements like corporate purpose, strategy, culture, and a climate fostering inclusion and diversity have an indirect impact. The study underscores the importance of cultivating an inclusive, supportive workplace that prioritizes employee well-being and empowerment, thus underscoring employees’ pivotal role in enhancing an organization's reputation

    Numerical Investigation of Shallow Depth Sloshing Absorbers for Structural Control

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    A liquid sloshing absorber consists of a container, partially filled with liquid. The absorber is attached to the structure to be controlled, and relies on the structure’s motion to excite the liquid. Consequently, a sloshing wave is produced at the liquid free surface within the absorber, possessing energy dissipative qualities. The behaviour of liquid sloshing absorbers has been well documented, although their use in structural control applications has attracted considerably less attention. Generally it is accepted that sloshing absorbers with lower liquid levels are more effective energy dissipaters than those with higher levels, although there has not yet been a study to reveal an ‘optimum’ design mechanism. The main limitation of numerically modelling such circumstances is the inherent complexity in the free surface behaviour, predictions of which are limited when using grid-based modelling techniques. Considering such limitations, Smoothed Particle Hydrodynamics (SPH) is used in this study to model a 2-dimensional rectangular liquid sloshing absorber. SPH is a Lagrangian method of solving the equations of fluid flow that is suitable to model liquid sloshing due its grid-free nature, and inherent ability to model complex free surface behaviour. The primary objective of this paper is to numerically demonstrate the effect of tuning a container's width, to complement previous work [6] on the effect of liquid depth. This study is in an attempt to reveal geometry that enables both effective energy transfer to sloshing liquid and to dissipate this energy quickly

    Sensitivity analysis of the tool for assessing safe manoeuvrability of ships in adverse sea conditions

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    In 2013, International Maritime Organization (IMO) introduced the Interim Guidelines for determining the minimum propulsion power to maintain the manoeuvrability of ships in adverse conditions. Considering the sufficiency of propulsion system in adverse sea conditions, the European project SHOPERA has developed alternative processes and tools for assessing safe manoeuvrability of ships. The main objective of these procedures is to identify the critical conditions where the vessel maintains its course keeping and manoeuvring ability at the vessel available propulsion power by using basic ship design values as input into the simplified methods proposed. Outcomes of this project were submitted and discussed in the 70th session of IMO’s Marine Environmental Protection Committee. In this paper, a brief description of these new assessment procedures is presented and a sensitivity analysis is conducted. The analysis is performed for a range of different open water propeller and hull resistance characteristics, hull – propeller interaction factors and engine power limit values, investigating the influence of these various performance parameters on the performance of the vessel

    Distributed Attack Monitoring Scheme for Islanded DC Microgrids

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