231 research outputs found
Valorization of cigarette butts for synthesis of levulinic acid as top value-added chemicals
Unprecedented in the literature, levulinic acid (LA), one of the top value-added intermediates of chemical industry, is obtained from cigarette butts as cellulose feedstock by means of a one-pot hydrothermal process carried out at 200 °C for 2 h and catalysed by phosphoric acid. The protocol avoids the use of more aggressive and toxic H2SO4 and HCl, that are generally employed on several cellulose sources (e.g. sludge paper), thus minimizing corrosion phenomena of plants. Neither chemical pre-treatment of butts nor specific purification procedure of LA are required. Notably, by simply modifying acid catalyst (e.g. using CH3COOH), another top value-added fine chemical such as 5-hydroxymethylfuraldehyde (HMF) is obtained, thus widening the scope of the method. Being cigarette filters a waste available in quantities of megatonnes per year, they represent an unlimited at no cost source of cellulose, thus enabling the up-scale to an industrial level of LA production
Operational Experience with a LHC Collimator Prototype in the CERN SPS
A full-scale prototype of the Large Hadron Collider (LHC) collimator was installed in 2004 in the CERN Super Proton Synchrotron (SPS) and has been extensively used for beam tests, for control tests and also LHC simulation benchmarking during four years of operation. This operational experience has been extremely valuable in view of the final LHC implementation as well as for estimating the LHC operational scenarios, most notably to establish procedures for the beam-based alignment of the collimators with respect to the circulating beam. These studies were made possible by installing in the SPS a first prototype of the LHC beam loss monitoring system. The operational experience gained at the SPS and the lessons learnt for the LHC operation are presented
Plans for a Superconducting H LINAC (SPL) at CERN
As part of the upgrade of the LHC injector complex at CERN, the construction of a 4 GeV Superconducting Proton Linac (the SPL, in fact an H- accelerator) is planned to begin in 2012. Depending upon physics requests, it should be upgradeable to 5 GeV and multi-MW beam power at a later stage. The construction of Linac4, its low energy front end, has started at the beginning of 2008. A full project proposal with a cost estimate for the low power version of the SPL aimed at improving LHC performance has to be ready for mid-2011. As a first step towards that goal, essential machine parameters like RF frequency, cooling temperature and accelerating gradient have recently been revisited and plans have been drawn for designing and testing critical components
Choice of Frequency, Gradient and Temperature for a Superconducting Proton Linac
The construction of a Superconducting Proton Linac is planned at CERN during the next decade. It is foreseen to be constructed in two stages: a low duty cycle, low-power linac (LPSPL) as an injector for a new 50 GeV synchrotron (PS2) replacing the present PS, which could be upgraded to a high-duty cycle, high-power linac (HPSPL), for the needs of future facility(ies) requiring a multi-MW beam power. In this paper we present the criteria which were used to choose the frequency, gradient, and cryogenic temperature of the SPL. Since these questions are common to other proposed high-power proton linacs, they may also be of use for other projects with similar specifications. The various design options are discussed as well as their impact on beam dynamics, cavity performance, power consumption, cryogenics,and overall efficiency
Assessment of the basic parameters of the CERN Superconducting Proton Linac
The construction of a 4GeV Superconducting Proton Linac (the SPL) is now part of the Long Term Plan of CERN, and the construction of Linac4, its low-energy front end, has begun. For mid-2011 the existing conceptual design of the SPL has to be refined and transformed into a project proposal. As a first step, basic parameters like RF frequency, accelerating gradient and operating temperature of the superconducting cavities have been re-assessed, taking into account the experience accumulated in the world during the recent years, especially for the SNS and the ILC projects. The conclusions confirm the validity of the initial choices, namely the RF frequency of 704.4MHz and the cooling temperature of ~ 2K. However the assumed gradients are estimated as optimistic: additional tests are necessary during the coming years to properly define the values to be used in the SPL design. This analysis is documented and its results are explained in this report
Upgrades Of the SPS, Transfer Line and LHC Injection Protection Devices For the HL-LHC Era
The challenging High Luminosity LHC (HL-LHC) beam requirements will lead in
the future to unprecedented beam parameters along the LHC injector chain. In
the SPS accelerator these requests translate into about a factor two higher
intensity and brightness than the present design performance. In addition to
the challenge of producing and accelerating such beams, these parameters affect
the resistance of the existing equipment against beam impact. Most of the
protection devices in the SPS ring, its transfer lines and the LHC injection
areas will be put under operational constraints which are beyond their design
specification. The equipment concerned has been reviewed and their resistance
to the HL-LHC beams checked. Theoretical and simulation studies have been
performed for the SPS beam scraping system, the protection devices and the dump
absorbers of the SPS-to-LHC transfer lines, as well as for the LHC injection
protection devices. The first results of these studies are reported, together
with the future prospects.Comment: 3 p. Presented at 4th International Particle Accelerator Conference
(IPAC 2013
A Comparation of Succession Law on Intestacy Between Chinese Mainland and Macao SAR
继承法与一个国家或地区的政治、经济制度、文化传统等有着密切的联系,与每个婚姻家庭息息相关。继承制度关系到公民财产所有权的保护,继承法在社会生活中具有重要的地位和作用。澳门回归十年,中国内地与澳门之间的往来频繁,交流范围逐渐扩展,涉澳婚姻家庭关系日益增多,继承问题也日渐突出。中国内地与澳门地区的法律同具大陆法传统,但两地间存在着许多差异。中国内地与澳门地区各有独立的继承法律制度,其中既有相近相容的共同规则,又有不容讳言的差异。因此,比较研究中国内地与澳门地区两法域的继承法,不仅具有理论意义,同时深具实践价值。 本文除引言与结语外,一共包括三章。 第一章比较中国内地和澳门地区法定继承制度历史沿...Succession is an important part of civil law. It not only has a close link with a country or region’s political, economic systems and cultural traditions, but also closely related with each marriage and family. Because the succession system related to the protection of citizens’ property rights, it plays an important role in social life. It has been over a decade of Macao's return. As the accele...学位:法学硕士院系专业:法学院法律系_民商法学(含劳动法学、社会保障法学)学号:1292007115403
The CARE accelerator R&D programme in Europe
Published online on JACoWCARE, an ambitious and coordinated programme of accelerator research and developments oriented towards high energy physics projects, has been launched in January 2004 by the main European laboratories and the European Commission. This project aims at improving existing infrastructures dedicated to future projects such as linear colliders, upgrades of hadron colliders and high intensity proton drivers. We describe the CARE R&D plans, mostly devoted to advancing the performance of the superconducting technology, both in the fields of RF cavities for electron or proton acceleration and of high field magnets, as well as to developing high intensity electron and proton injectors. We highlight some results and progress obtained so far
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