Computation of Resistive Wakefields

We evaluate longitudinal resistive wakefields for cylindrical beam pipes numerically and compare the results with existing approximate formul\ae. We consider an ultra-relativistic bunch traversing a cylindrical, metallic tube for a model in which the wall conductivity is taken to be first independent and second dependent on frequency, and we show how these can be included simply and efficiently in particle tracking simulations. We also extend this to higher order modes, and to the transverse wakes. This full treatment can be necessary in the design of modern nano-beam accelerators

Analysis of price determinants in the case of Airbnb listings

Nowadays, the role of the sharing economy in tourism increases, the number of people involved as guests or hosts rising day by day. This dynamic generates a viable alternative to the traditional services, allowing tourists to customise their trips and enrich their experiences. This paper focuses on accommodation services, investigating the factors influencing the prices established by Airbnb hosts. Using structural equation modelling, the authors analyse the influence of different categories of factors (listing’s characteristics, hosts’ involvement, listing’s reputation, listing’s location, and rental policies) on the average daily rate. The results emphasise that the hosts establish the listing’s price based on listing’s characteristics and on their involvement – the owners managing only one listing and the ones charging a security deposit value more their involvement, while the other hosts focus more on the listings’ characteristics. The location of the listing counts for experienced owners, while for opportunist owners it has no importance. The listings’ reputation has a negative impact on the price, contrary to the conclusions achieved in other studies, an aspect that supports the idea that price determinants differ across regions

Background Calculations for the High Energy Beam Transport Region of the European Spallation Source

Expected backgrounds in the final accelerator-to-target region of the European Spallation Source, to be built in Lund, Sweden, have been calculated using the MCNPX program. We consider the effects of losses from the beam, both along the full length and localised at the bending magnets, and also backsplash from the target. The prompt background is calculated, and also the residual dose, as a function of time, arising from activation of the beam components. Activation of the air is also determined. The model includes the focussing and rasterising magnets, and shows the effects of the concrete walls of the tunnel. We give the implications for the design and operation of the accelerator

Comparison of MERLIN/SixTrack for LHC Collimation Studies

Simulations of the LHC collimation system have been carried out in previous years with the well known SixTrack code with collimation features. MERLIN is a C++ accelerator physics library that has been extended to perform collimation studies. The main features of the code are: its modular nature, allowing the user to easily implement new physics processes such as resistive wakefields and synchrotron radiation, improved scattering routines and the MPI protocol for parallel execution. MERLIN has been configured to use the same scattering routines as SixTrack in order to benchmark the code for the LHC collimation system. In this paper we present a detailed comparison between MERLIN and SixTrack for optics and cleaning inefficiency calculation

Hi-Lumi LHC Collimation Studies with MERLIN Code

The collimation system is key to the successful operation of the LHC. Measurements and simulations of the previous run at 4 TeV have shown that the system is ready for the next step, running at 7 TeV, but at the same time some sensitive cleaning locations have been identified. In particular the dispersion suppressors downstream of the betatron cleaning region in IR7 are sensitive to single diffractive scattered protons from the collimator jaws. These particles can lead to magnet quenching. The MERLIN C++ library has been developed to exploit the functionality of an object oriented code, with improved collective effects and scattering routines. New single diffractive and elastic scattering routines, based on a fit of existing experimental data with the Regge theory of soft interactions of high energy scattering, is implemented in MERLIN. In this paper we present the impact of the new single diffractive scattering physics on the cleaning inefficiency of the LHC collimation system for the Achromatic Telescope Squeezing (ATS) PreSqueeze optics scheme, for the HL-LHC project. The results are compared with the same loss map calculated using a SixTrack+K2 like scattering routine

Simulating the LHC collimation system with the accelerator physics library MERLIN, and loss map results

We present large scale simulations of the LHC collimation system using the MERLIN code for calculations of loss maps, currently using up to 1.5 × 10**9 halo particle

Ring exchange in solid ³He and La₂CuO₄

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Study of Perceptions on Cultural Events’ Sustainability

Cultural events and festivals can have a significant and important influence on the development of local communities. Their utilization of the endogenous resources of an area means that these events, most often, have a positive impact on the local economy. Quite consequentially, they may also extend the socio-cultural opportunities of local citizens. However, their utilization of time and space does raise concerns regarding environmental impact. Therefore, it is imperative that stakeholders study their net impact on a region. This present paper examines the economic, socio-cultural, and environmental impact of the Transilvania International Film Festival (TIFF). With a history of 15 editions, the festival gathers, year by year, an increasing number of people in Cluj-Napoca. The growth of the event has had unmistakable and important effects on the city. The purpose of the paper is to analyze resident participants’ perceptions on economic, socio-cultural, and environmental effects. To reach this goal, an exploratory and descriptive research was conducted. Both primary and secondary data were used in the analysis, the questionnaire being the main tool used for collecting data about participants’ perceptions. The results emphasize the positive effects at the socio-cultural level. The festival provides multiple possibilities to spend free time in a pleasant way, it sustains the development of cultural life, and it improves the educational and the cultural level of community. Moreover, the festival does not influence, in a negative manner, the moral principles of the society and it does not generate an increase in crime rate. From the economic point of view, the festival has the capacity to attract investments and additional revenues for the local government, it sustains the development of the city infrastructure, and it creates opportunities for residents to develop new economic activities. Lastly, from the environmental point of view, the festival sustains the improvement of environmental issues, it does not generate important traffic problems, and it does not deteriorate touristic resources