95 research outputs found
Clinical Application of the Hanover Classification for Iatrogenic Bile Duct Lesions
Background. There is only limited evidence available to justify generalized clinical classification and treatment recommendations for iatrogenic bile duct lesions. Methods. Data of 93 patients with iatrogenic bile duct lesions was evaluated retrospectively to analyse the variety of encountered lesions with the Hanover classification and its impact on surgical treatment and outcomes. Results. Bile duct lesions combined with vascular lesions were observed in 20 patients (21.5%). 18 of these patients were treated with additional partial hepatectomy while the majority were treated by hepaticojejunostomy alone (n = 54). Concomitant injury to the right hepatic artery resulted in additional right anatomical hemihepatectomy in 10 of 18 cases. 8 of 12 cases with type A lesions were treated with drainage alone or direct suture of the bile leak while 2 patients with a C2 lesion required a Whipple's procedure. Observed congruence between originally proposed lesion-type-specific treatment and actually performed treatment was 66–100% dependent on the category of lesion type. Hospital mortality was 3.2% (n = 3). Conclusions. The Hannover classification may be helpful to standardize the systematic description of iatrogenic bile duct lesions in order to establish evidence-based and lesion-type-specific treatment recommendations
The use of weak waves as diagnostic tracers in unsteady flows
Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.This paper examines the tracing of the trajectories of weak waves behind a shock wave induced flow in order to establish how the domain shape influences the flow both from a spatial and temporal perspective. The basic principle is that if a particle produces a series of point disturbances in a flow field the perturbations induced will propagate outwards at the local sonic velocity whilst at the same time being convected along with the local flow velocity. A number of issues may be identified for an unsteady flow. Firstly the flow field at later times may be influenced by perturbations produced at earlier times. Secondly, if the positions of the perturbations can be monitored as a function of time then the trajectory and velocity of the particle may be deduced. Thirdly, if a perturbation arises from a point on a boundary then its influence, if any, on any particular part of the flow can be established.cs201
Aerodynamics of a Supersonic Projectile in Proximity to a Solid Surface
Flow around a Mach 2.4 NATO 5.56 mm projectile in close proximity to a ground plane was investigated using computational fluid dynamics for a direct numerical reproduction of live-range experiments. The numerical approach was validated against both the live-range tests and subsequent wind-tunnel experiments. A nonspinning half-model and a full, spinning projectile were examined to clarify the influence of rotation. Multiple ground clearances were tested to obtain clear trends in changes to the aerodynamic coefficients, and the three-dimensional propagation and reflection of the shock waves were considered in detail. The behavior of the flow in the near wake was also studied as ground clearance was reduced. Ground proximity was found to significantly increase the drag force acting on the projectile, as well as generate a force normal to the ground and an increased side force, when ground clearance was less than one diameter. For clearances between approximately 0.4 and 1 diameter, the pitching moment produced was nose-down. For lower clearances, a more distinct nose-up trend was produced. The generated side force was orders of magnitude lower than the normal and drag forces
On the measurement of laser-induced plasma breakdown thresholds
The breakdown threshold of a gas exposed to intense laser-radiation is a function of gas and laser properties. Breakdown thresholds reported in the literature often vary greatly and these differences can partially be traced back to the method that is typically used to determine breakdown thresholds. This paper discusses the traditional method used to determine breakdown thresholds and the potential errors that can arise using this approach, and presents an alternative method which can yield more accurate data especially when determining breakdown thresholds as functions of gas pressure
Segregation and mixing of granular material in industrial processes
Within the EU-funded PARDEM network mixing and segregation are studied in silos and heaps, agitated mixers and fluidized beds. A method is presented with which mixing and segregation can be characterized, adapted for quasi-static to dynamic systems and applied at the global system level as well as at the local level. This paper attempts to give an overview of the applicability of this analysis by providing three instances, being chute flow representing flow down a heap, agitated mixing and fluidization, in which the method is applied
Sustainable Human Development: Corporate Challenges and Potentials the Case of Bayer CropScience's Cotton Seed Production in Rural Karnataka (India)
This paper aims to explore concepts, methods and empirical results of potential impacts of Transnational Corporations (TNC) on Sustainable Human Development (SHD) in emerging market countries. In doing so, a further major goal is to explain, illustrate and discuss how the theoretical CA framework used in the GeNECA project2 can be applied to corporate SHD impacts. Our findings are based on the case of Bayer CropScience’s Model Village Project in rural Karnataka, India. To achieve our goals, we first establish a theoretical framework for assessing corporate impacts on SHD to capture SHD effects. Thereafter, we introduce the case of Bayer CropScience’s seed production in rural India, for which a “Model Village Project (MVP)” has been established to explore ways, potentials and challenges of promoting SHD of the villagers and corporate goals in a win-win-strategy. Afterwards, we explain methodological requirements, our representative database for the quantitative analyses, and the qualitative methods that we use for project evaluation. Based on findings of the authors’ external evaluation of the MVP, we discuss the baseline situation in the model villages with respect to corporate potentials, challenges and limitations to foster SHD impacts. Methodologically, we find the combination of quantitative representative methods and qualitative assessments to be most effective to capture corporate potentials and risks. Furthermore it turns out to be promising to extend the analyses beyond standardized benchmarks like the MDGs. We show that major determinants of SHD established in the paper result in a portfolio of corporate opportunities and risks. For instance, the reality of underemployment in the model villages provides specific corporate opportunities like an abundant pool of labor supply. However, it also produces corporate risks, e.g. lack of capital available for necessary investment by suppliers who frequently suffer from poverty, risk of over-indebtedness and a resulting inability to accumulate enough capital and to raise productivity. In the comprehensive opportunity and riskportfolio of this Bayer CropScience case, we find abundant potential business cases which we discuss further in the text. We conclude that corporate potentials as well as risks of corporate neglect and violations of people-centered SHD also depend on how much the villagers are enabled and empowered to make most of their agency as individuals and as groups. Furthermore, it depends on trust building as a prerequisite of awareness raising of the villagers themselves, so that they are willing and able to participate successfully in the undertaken procedures
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