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Effect of baffles on performance of fluid catalytic cracking riser

Particuology 2018年第3期16卷 18-30页

作者： milinkumar T. Shah Vishnu K. Pareek geoffrey m. Evans Ranjeet P. Utikar Department of Chemical Engineering Curtin University Western Australia Australia Department of Chemical Engineering University of Newcastle New South Wales Australia

Increasing demand of automobile fuel and a need to process heavier crude oil makes it imperative to find improvements to the design of existing fluid catalytic cracking （FCC） units. Several modifications to the design of the riser section of FCC units have been suggested in previous studies including： improved feed nozzle designs, multiple nozzle configurations, internal baffles, and novel two-stage-riser systems. In this study, we investigate the effects of baffles on the performance of FCC risers using computational fluid dynamics simulations. In this study, predictions from a basis model （without baffles） are compared with those from four different configurations including：（i） 5-cm baffles at 5-m spacing, （ii） 7.5-cm baffles at 5- m spacing, （iii） 10-cm baffles with 5-m spacing, （iv） lO-cm baffles at 2.5-m spacing, and （v） lO-cm baffles at 1-m spacing. The baffles force the catalyst away from wails toward the center of the riser, enhancing the radial dispersion of the catalyst and the heat transfer inside the riser. The use of longer baffles and smaller spacings further increases the dispersion, yielding more homogeneous radial profiles. The changes in the radial dispersion result in variations in the conversion, yields, and pressure drops. The baffles increase conversion of vacuum gas oil （VGO） and the yield of gasoline. However, the simulations showed that longer baffles and a larger number of baffles did not always give a higher yield or higher conversion. Among the simulated configurations, the 5-cm baffles at 5-m spacing gave the highest conversion of VGO, whereas the 10-cm baffles at 1 -m spacing resulted in the highest yield of the gasoline. Thus, rational optimization of baffle configurations is required to achieve optimal performance.

关键词： Fluid catalytic cracking Riser Baffles Computational fluid dynamics

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Predicting maximum Lifespan Limits at mean menopausal Age

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Journal of mathematical Research with Applications 2025年第1期 133-142页

作者： m.SUmATHI S.ANTONY CARLA Department of mathematics N.M.S.S.Vellaichamy Nadar College Research Scholar (Part-time) Madurai Kamaraj University

The age at which a woman enters natural menopause has also been associated to death from any cause. menopause is a natural component of aging that happens between the ages of 45 and 55, with the average menopausal age being 51. Previous research has revealed the age at which women reach menopause, but there is no evidence to support the link between menopause and longevity. We made a study in assessing the limits of maximum lifespan at menopausal age in our previous article. In this paper, we aim to predict the maximum lifespan of women at mean menopausal age.

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Atypical presentation of a ventricular papillary fibroelastoma

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Journal of Geriatric Cardiology 2017年第8期14卷 534-535页

作者： Julio Perez-downes Harold Dietzius Saif Ibrahim Vasant Jayasankar Leslie Oberst Department of medicine University of Florida College of Medicine-Jacksonville USA Department of Cardiology Memorial tIospital USA Department of Cardiology University of Florida College of Medicine-Jacksonville USA Department of Cardiothoracic Surgery Memorial Hospital USA

Papillary fibroelastoma cardiac tumor. The most is the most common valvular common non-valvular site these minors present is the left ventricle, where they usually manifest as ischemic strokes or myocardial infarction. Although these tumors also have a risk of embolization into the peripheral system, reports of such events are exceedingly rare.

关键词： Fibroelastoma Ischemia myocardium Neoplasm Thrombosis

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Residual force enhancement due to active muscle lengthening allows similar reductions in neuromuscular activation during position-and force-control tasks

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Journal of Sport and Health Science 2020年第6期9卷 670-676页

作者： Rhiannon marion geoffrey A.Power Department of Human Health and Nutritional Sciences College of Biological SciencesUniversity of GuelphGuelphOntarioN1G 2W1Canada

Background:Residual torque enhancement(rTE)is the increase in torque observed during the isometric steady state following active muscle lengthening when compared with a fixed-end isometric contraction at the same muscle length and level of neuromuscular *** the rTE state,owing to an elevated contribution of passive force to total force production,less active force is required,and there is a subsequent reduction in *** vivo studies of rTE reporting an activation reduction are often performed using a dynamometer,where participants contract against a rigid restraint,resisting a torque *** has yet to be investigated during a position task,which involves the displacement of an inertial load with positional ***:A total of 12 participants(6 males,6 females;age=22.8±1.1 years,height=174.7±8.6 cm,mass=82.1±37.7 kg;mean±SD)completed torque-and position-matching tasks at 60%maximum voluntary contraction for a fixed-end isometric contraction and an isometric contraction following active lengthening of the ankle ***:There were no significant differences in activation between torque-and position-matching tasks(p=0.743),with^27%activation reduction following active lengthening for both task types(pmetric torque-control conditions to position-controlled contractions that represent different tasks of daily living.

关键词： Eccentric Electromyography History dependence of force Position tasks Residual force enhancement

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Endovascular thrombectomy for stroke: current best practice and future goals

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Stroke & Vascular Neurology 2016年第1期1卷 16-22页

作者： Bruce C V Campbell geoffrey A Donnan Peter J mitchell Stephen m Davis Department of medicine and Neurology Melbourne Brain Centre at the Royal Melbourne HospitalUniversity of MelbourneParkvilleVictoriaAustralia The Florey Institute of Neuroscience and mental Health University of MelbourneParkvilleVictoriaAustralia Department of Radiology Royal Melbourne HospitalUniversity of MelbourneParkvilleVictoriaAustralia

Endovascular thrombectomy for large vessel ischaemic stroke substantially reduces disability,with recent positive randomised trials leading to guideline changes *** review discusses in detail the evidence provided by recent randomised trials and metaanalyses,the remaining areas of uncertainty and the future directions for *** data from existing trials have demonstrated the robust benefit of endovascular thrombectomy for internal carotid and proximal middle cerebral artery *** remains for more distal occlusions where the efficacy of alteplase is greater,less tissue is at risk and the safety of endovascular procedures is less *** artery occlusion was excluded from the trials,but with a dire natural history and proof of principle that rapid reperfusion is effective,it seems reasonable to continue treating these patients pending ongoing trial *** has been no evidence of heterogeneity in treatment effect in clinically defined subgroups by age,indeed,those aged>80 years have at least as great an overall reduction in disability and reduced *** there was no heterogeneity across the range of baseline stroke severities included in the *** that routine use of general anaesthesia reduces the benefit of endovascular thrombectomy is increasing and conscious sedation is generally preferred unless severe agitation or airway compromise is *** impact of time delays has become clearer with description of onset to imaging and imaging to reperfusion *** in the onset to imaging reduce the proportion of patients with salvageable brain ***,in the presence of favourable imaging,rapid treatment appears beneficial regardless of the onset to imaging time *** to reperfusion delays lead to decay in the clinical benefit achieved,particularly in those with less robust collateral *** brain imaging options to assess prognosis have various advantages and disadvan

关键词： routine epoch benefit

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Politeness: Is There an East-West Divide?

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外国语 2005年第6期28卷 3-31页

作者： geoffrey Leech Lancaster University UK

The theory of politeness of Brown and Levinson (1978, 1987) has remained the most seminal and influential starting point for cross-cultural and cross-linguistic contrastive pragmatics. Yet is has also provoked countervailing arguments from Ide (1989, 1993), matsumoto (1989), Gu (1990), mao (1994) and others, pointing out a Western bias in Brown and Levinson’s theory, particularly in their construal of the concept of ‘face’, in their overemphasis on face-threat and their assumption of individualistic and egalitarian motivations, as opposed to the more group-centred hierarchy-based ethos of Eastern societies. This leads to the question in the title of this article: Is there an East-West divide in politeness? The following argument will be presented. There is an overarching framework for studying linguistic politeness phenomena in communication: a common principle of politeness (Leech, 1983, 2002) and a Grand Strategy of Politeness (GSP), which is evident in common linguistic behaviour patterns in the performance of polite speech acts such as requests, offers, compliments, apologies, thanks, and responses to these. The GSP says simply: In order to be polite, a speaker communicates meanings which (a) place a high value on what relates to the other person (typically the addressee), (mAJOR CONSTRAINT) and (b) place a low value on what relates to the speaker. (mINOR CONSTRAINT). It is clear from many observations that constraint (a) is more powerful than constraint (b). The following hypothesis will be put forward, and supported by very limited evidence: that the GSP provides a very general explanation for communicative politeness phenomena in Eastern languages such as Chinese, Japanese and Korean, as well as in Western languages such as English. This is not to deny the importance of quantitative and qualitative differences in the settings of social parameters and linguistic parameters of politeness in such languages. A framework such as the GSP provides the parameters of

关键词：跨文化交际礼貌原则语用学英语

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Why frequency can no longer be ignored in ELT？

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外语教学与研究 2011年第1期43卷 3-20页

作者： geoffrey Leech Lancaster University

I begin this paper with a brief survey of how frequency — in particular, frequency of words — had a role in language learning in the days before electronic corpora existed. Then I consider how the "corpus revolution" made frequency information available in a totally unprecedented way from the 1960s onward. Finally I discuss the usefulness of frequency to the language learner and teacher, and some new directions in applied linguistics favourable to frequency.

关键词： frequency corpus language learning

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The role of frequency in ELT: New corpus evidence brings a re-appraisal

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外语教学与研究 2001年第5期33卷 328-339页

作者： geoffrey Leech LancasterUniversity

This paper reconsiders the value of frequency information in ELT, taking into account new evidence provided by corpora of native speakers’ English (e.g. the British National Corpus) and evidence available through new dictionaries and grammars making use of such corpus information. Some examples are given, showing how information about frequency in spoken and written English may cause reappraisal of assumptions common in pedagogical grammar. It is argued that frequency as a principle for the selection and prioritising of language content has been neglected, and the availability of corpus_derived frequency information means that this neglect can now be rectified. However, frequency must be considered alongside other factors that have a bearing on sequencing in ELT materials, such as dispersion, coverage, learnability and communicative need. Also, it is important to bear in mind that findings based on corpora of native_speaker English must be complemented by those based on corpora of learner English, and of the native language of the learners.

关键词：英语教学教学方法词汇知识语法教学内容

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The contribution of Asian scientists to global research in andrology

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Asian Journal of Andrology 1999年第1期1卷 7-12页

作者： geoffrey mH WAITES Clinic for Infertility and Gynaecological Endocrinology University Hospital of Geneva SWITZERLAND and Department of Medicine Unnversity of Sydney Sydney NSW 2006 AUSTRALIA

Aim: To present a personal account of the involvement of the World Health Organization (WHO) in the collaborativedevelopment in Asia of those areas of andrology concerned with male contraception and reproductive ***: The andrology training through workshops and institution support undertaken by the WHO HumanReproduction Programme (HRP) and how they contributed to the strengthening of andrology research in Asia aresummarised. Results: The author's experience and the Asian scientific contributions to the global research in thefollowing areas are reviewed: the safety of vasectomy and the development of new methods of vas occlusion; gossypoland its failure to become a safe, reversible male antifertility drag; Tripterygium and whether its pure extracts will passthrough the appropriate toxicology and phased clinical studies to become acceptable contraceptive drugs; hormonalmethods of contraception for men. Conclusion: The WHO policy of research capacity building through training andinstitution strengthening, together with the collaboration of Asian andrologists, has created strong National institutionsnow able to direct their own programmes of research in clinical and scientific andrology.

关键词： andrology Asia contraception vas occlusion gossypol Tripterygium hormonal methods World Health Organization

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A state-of-the-art review on single drop study in liquid–liquid extraction:Experiments and simulations

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Chinese Journal of Chemical Engineering 2019年第12期27卷 2857-2875页

作者： Jiyizhe Zhang Yundong Wang geoffrey WStevens Weiyang Fei The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China Department of Chemical Engineering The University of MelbourneParkvilleVictoria 3010Australia

The experimental and numerical investigations of single drop in liquid/liquid extraction system have been reviewed with particular focus on experimental techniques and computational fluid dynamic simulation *** surveys of available experimental techniques and numerical approaches for single drop rising and falling were ***,single drop mass transfer was also reviewed both experimentally and ***,single drop breakage and coalescence process and the influencing factors were summarized and compared,so as to establish sub-models for population balance *** directions on single drop mass transfer,drop breakage and coalescence were *** is believed that the single drop is a powerful tool to assist extraction process design from lab-scale to pilot-scale.

关键词： Solvent extraction mass transfer Single drop Drop breakage and coalescence CFD simulation Population balance model

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