109 research outputs found
The regulatory framework for the reduction of greenhouse gas emissions from international shipping
International shipping carries 80 per cent of global trade by volume and over 70 per cent by value. This significant global activity comes with the concern that the greenhouse gas (GHG) emissions from international shipping lead to adverse effects on climate, human health and marine ecosystems. There have been international efforts to address this problem by improving regulation, principally by the United Nations (UN), the International Maritime Organization (IMO), the shipping industry, flag States and port States. The international climate change regime under the United Nations Framework Convention on Climate Change (UNFCCC) process and the IMO through its Marine Environment Protection Committee have been grappling with this issue, and GHG emissions from international shipping have been partially regulated by amendments to Annex VI to the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78) in 2011 and 2014.
This thesis examines the evolution and adequacy of the current regulatory framework for the reduction of GHG emissions from international shipping. It discusses the applicability of international environmental law principles to the reduction of GHG emissions from ships and assesses the responses of the key stakeholders to the challenge of reducing GHG emissions. These responses and legal principles are then analysed to identify gaps in the regulatory framework. It concludes that there are deficiencies in the current legal, policy and institutional frameworks regulating GHG emissions from international shipping. The thesis proposes options for legal and institutional reforms to improve the regulatory framework for the reduction of GHG emissions from international shipping
Greenhouse gas emissions from international shipping: the response from China\u27s shipping industry to the regulatory Iinitiatives of the International Maritime Organization
The International Maritime Organization (IMO) received its mandate to regulate shipping greenhouse gas (GHG) emissions from the Kyoto Protocol. However, the IMO Convention and the UN Convention on the Law of the Sea also provide it with competence in this area. In exercising its mandate, the IMO has developed regulatory initiatives. Chinaâs shipping industry is playing a growing role in the international shipping market, and its response to these initiatives will have a substantial effect on the future application of these regulations. This article analyses the GHG mandate of the IMO, examines the main outcomes achieved within the organization on this issue, and assesses the response from Chinaâs shipping industry to this issue. It concludes that the interests of the shipping industries from developing countries will need to be taken into account in the development of regulatory efforts if a consensus is to be achieved in the global reduction of GHG emissions from ships
Structure and motion design of a mock circulatory test rig
Mock circulatory test rig (MCTR) is the essential and indispensable facility in the cardiovascular in vitro studies. The system configuration and the motion profile of the MCTR design directly influence the validity, precision, and accuracy of the experimental data collected. Previous studies gave the schematic but never describe the structure and motion design details of the MCTRs used, which makes comparison of the experimental data reported by different research groups plausible but not fully convincing. This article presents the detailed structure and motion design of a sophisticated MCTR system, and examines the important issues such as the determination of the ventricular motion waveform, modelling of the physiological impedance, etc., in the MCTR designing. The study demonstrates the overall design procedures from the system conception, cardiac model devising, motion planning, to the motor and accessories selection. This can be used as a reference to aid researchers in the design and construction of their own in-house MCTRs for cardiovascular studies
Review of Zero-D and 1-D Models of Blood Flow in the Cardiovascular System
<p>Abstract</p> <p>Background</p> <p>Zero-dimensional (lumped parameter) and one dimensional models, based on simplified representations of the components of the cardiovascular system, can contribute strongly to our understanding of circulatory physiology. Zero-D models provide a concise way to evaluate the haemodynamic interactions among the cardiovascular organs, whilst one-D (distributed parameter) models add the facility to represent efficiently the effects of pulse wave transmission in the arterial network at greatly reduced computational expense compared to higher dimensional computational fluid dynamics studies. There is extensive literature on both types of models.</p> <p>Method and Results</p> <p>The purpose of this review article is to summarise published 0D and 1D models of the cardiovascular system, to explore their limitations and range of application, and to provide an indication of the physiological phenomena that can be included in these representations. The review on 0D models collects together in one place a description of the range of models that have been used to describe the various characteristics of cardiovascular response, together with the factors that influence it. Such models generally feature the major components of the system, such as the heart, the heart valves and the vasculature. The models are categorised in terms of the features of the system that they are able to represent, their complexity and range of application: representations of effects including pressure-dependent vessel properties, interaction between the heart chambers, neuro-regulation and auto-regulation are explored. The examination on 1D models covers various methods for the assembly, discretisation and solution of the governing equations, in conjunction with a report of the definition and treatment of boundary conditions. Increasingly, 0D and 1D models are used in multi-scale models, in which their primary role is to provide boundary conditions for sophisticate, and often patient-specific, 2D and 3D models, and this application is also addressed. As an example of 0D cardiovascular modelling, a small selection of simple models have been represented in the CellML mark-up language and uploaded to the CellML model repository <url>http://models.cellml.org/</url>. They are freely available to the research and education communities.</p> <p>Conclusion</p> <p>Each published cardiovascular model has merit for particular applications. This review categorises 0D and 1D models, highlights their advantages and disadvantages, and thus provides guidance on the selection of models to assist various cardiovascular modelling studies. It also identifies directions for further development, as well as current challenges in the wider use of these models including service to represent boundary conditions for local 3D models and translation to clinical application.</p
Suction force-suction distance relation during aspiration thrombectomy for ischemic stroke: A computational fluid dynamics study
Acute Ischemic Stroke (AIS) is the major type of stroke occurring in patients. Aspiration thrombectomy, which uses suction to remove the thrombosis, is a promising technique in the clinical treatment of AIS patients. In this research a computational fluid dynamics (CFD) analysis was conducted to model the blood flow dynamics in a simplified cerebral model during an aspiration thrombectomy procedure. The flow system being analysed was a typical in vitro cerebral flow model, and the system parameters were set based on the clinical and in vitro data reported in open literature. The simulated flow field features showed good correlation with the in vitro response as reported in literature. The CFD study provides detailed technical data including the peak velocity occurring at the catheter tip and the suction force/suction distance relation during the aspiration thrombectomy procedure, which are useful new knowledge and have the potential to influence future catheter design as well as clinical operational protocols used during thrombectomy intervention
Impact of entrepreneurship education in colleges and universities on entrepreneurial entry and performance
This study aims to investigate the impact of three established
approaches to entrepreneurship education, Theory, Competition
and Incubation, on entrepreneurial entry and performance.
Propensity score matching is used to compare three cohorts from
the alumni of a business college in China who completed entrepreneurship
courses with their respective matched sample of
similar individuals who did not. The findings suggest that
Incubation significantly increases the probability of new venture
creation. Theory, and participation in entrepreneurial business
plan Competition(s) positively affect only those students that are
non-management majors. Analysis including multiple linear
regression indicates that Incubation has a positive impact on new
venture sales revenue, profit before tax and the number of
employees. The effect of Theory and Competition on new venture
performance is not significant. This study extends the current
knowledge of entrepreneurship education by providing new
empirical evidence for the proposition that entrepreneurship can
be learned, and the relative impact of these three types of education.
The findings have direct implications for policymakers, educational
executives, researchers, and others interested in
encouraging entrepreneurial activity
Possible interpretation of the (10610) and (10650) in a chiral quark model
Motivated by the two charged bottomonium-like resonances (10610) and
(10650) newly observed by the Belle collaboration, the possible molecular
states composed of a pair of heavy mesons, , etc (in S-wave), are investigated in the framework of chiral quark
models by the Gaussian expansion method. The bound states and
with quantum numbers , which are good
candidates for the and respectively, are obtained.
Other three bound states with ,
with are predicted. These
states may be observed in open-bottom or hidden-bottom decay channel of highly
excited . When extending directly the quark model to the hidden color
channel of the multi-quark system, more deeply bound states are found. Future
experimental search of those states will cast doubt on the validity of applying
the chiral constituent quark model to the hidden color channel directly.Comment: 13 pages, 1 figure, title and some arguments in the abstract and
section 5 are revised, results unchange
Pressure-Modulated Structural and Magnetic Phase Transitions in Two-Dimensional FeTe: Tetragonal and Hexagonal Polymorphs
Two-dimensional (2D) Fe-chalcogenides with rich structures, magnetisms and
superconductivities are highly desirable to reveal the torturous transition
mechanism and explore their potential applications in spintronics and
nanoelectronics. Hydrostatic pressure can effectively stimulate novel phase
transitions between various ordered states and to plot the seductive phase
diagram. Herein, the structural evolution and transport characteristics of 2D
FeTe were systematically investigated under extreme conditions through
comparing two distinct symmetries, i.e., tetragonal (t-) and hexagonal (h-)
FeTe. We found that 2D t-FeTe presented the pressure-induced transition from
antiferromagnetic to ferromagnetic states at ~ 3 GPa, corresponding to the
tetragonal collapse of layered structure. Contrarily, ferromagnetic order of 2D
h-FeTe was retained up to 15 GPa, evidently confirmed by electrical transport
and Raman measurements. Furthermore, the detailed P-T phase diagrams of both 2D
t-FeTe and h-FeTe were mapped out with the delicate critical conditions. We
believe our results can provide a unique platform to elaborate the
extraordinary physical properties of Fe-chalcogenides and further to develop
their practical applications.Comment: 22 Pages, 5 Figure
Closing the Loop: Modelling of Heart Failure Progression from Health to End-Stage Using a Meta-Analysis of Left Ventricular Pressure-Volume Loops
Introduction The American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for the classification of heart failure (HF) are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV) pressure-volume (PV) loop data and secondly use the LV PV loop data to create stage specific HF models. Methods and Results A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV), ejection fraction (EF%) decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax). Conclusions For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails
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