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Sediment Problem at Alvkarleby Power Station

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Small Hydro Power News 2006年第1期23卷 25-28页

作者： James Yang Nils Johansson Vattenfall Utveckling ab Alvkarleby Sweden swedpower ab Alvkarleby Sweden

Alvkarleby hydropower station, with five old Francis and one new Kaplan turbines, draws water from the natural river through a 250- m long artificial headrace. Autumn 1995 a hole, caused obviously by sand abrasion, was discovered in the headcover of one Francis unit （G1）, followed by new holes found in 1997 and 1998. Investigations are made, with the purpose of identifying the origin of the sediment and understanding its behavior in the headrace. Several locations along the river are examined through field observations, echo sounding and diving, aiming at locating the source of the sediment. This ends without definite conclusion, therefore whether the sediment transport will cease can not be answered. Assuming the sediment transport will continue, hydraulic model tests are made to examine the behavior of sand transport in the headrace. The results show that irrespective of how the old Francis units are operated, the sediment is transported along the right side of the old canal, not along the left as expected before the model was built. Strong bottom currents towards the Francis unit G I carry sand with it, which accounts for the wear of its headcover. Efforts are now made to study potential measures for sediment removal from the headrace.

关键词：水电站小水电泥沙水资源管理

Hydropower and Sustainable Development-A Matter of Ethical, Social and Environmental Considerations

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Hydropower and Sustainable Development-A Matter of Ethical, ...

Study of vibrating foundations considering soil-pile-structure interaction for practical applications

联合国水电与可持续发展研讨会

作者： Bjrn Svensson Urban Norstedt swedpower ab PO Box 527 SE-162 16 Stockholm Vattenfall ab SE-162 87 Stockholm Sweden

Electrification is a vital precondition for economic development and improved quality of life. Electric lights open doors to a new world, and electric power is an essential requirement for efficient solutions to alleviate poverty and increase the well-being of people. However, the generation of electricity is never without adverse effects to the environment. Some effects are restricted to the immediate surroundings of the power plants, whereas others, such as releases of greenhouse gases, have global extension. Development of hydropower and other renewable energy sources are needed in order to curb global warming. Although hydropower construction and operation has obvious local or regional effects, its impact on biodiversity is probaly comparable to or less than extraction of biomass fuel when considering the degree of service it provides. Yet, the exploitation of hydropower resources is a massive undertaking requiring responsibility towards the environment. This paper outlines in general terms the ethics, socioeconomics and environmental aspects of hydropower development and operation.

关键词： hydropower hydroelectric renewable energy sustainable development biodiversity greenhouse gas socioeconomics ethics

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Earthquake Engineering and Engineering Vibration 2008年第3期7卷 321-327页

作者： Han Yingcai Fluor Calgary AB Canada

An investigation of soil-pile-structure interaction is carried out, based on a large reciprocating compressor installed on an elevated concrete foundation （table top structure）. A practical method is described for the dynamic analysis, and compared with a 3D finite element （FE） model. Two commercial software packages are used for dynamic analysis considering the soilpile-structure interaction （SPSI）. Stiffness and damping of the pile foundation are generated from a computer program, and then input into the FE model. To examine the SPSI thoroughly, three cases for the soil, piles and superstructure are considered and compared. In the first case, the interaction is fully taken into account, that is, both the superstructure and soil-pile system are flexible. In the second case, the superstructure is flexible but fixed to a rigid base, with no deformation in the base （no SSI）. In the third case, the dynamic soil-pile interaction is taken into account, but the table top structure is assumed to be rigid. From the comparison beteen the results of these three cases some conclusions are made, which could be helpful for engineering practice.

关键词： soil-pile-structure interaction soil dynamics structural dynamics vibrating foundation

Review on docosahexaenoic acid in poultry and swine nutrition:Consequence of enriched animal products on performance and health characteristics

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Animal Nutrition 2019年第1期5卷 11-21页

作者： Sophie A.Lee Natasha Whenham Michael R.Bedford ab Vista Marlborough

Omega-3 polyunsaturated fatty acids(n-3 PUFA) are linked to a variety of health benefits against human disorders and disease. However, the typical western diet is generally low in n-3 PUFA and high in n-6 PUFA, suggesting that the recommended intake of these essential fatty acids is seldom ***, dietary enrichment of animal meat and eggs with n-3 PUFA could help increase consumption of these fatty acids. Fish oils and microalgae(MA) are rich sources of long chain n-3 PUFA, specifically eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA). Feeding these marine products has been shown to increase DHA content of tissues and yolk, however, this may also lead to an increased requirement for anti-oxidants to prevent oxidative deterioration and associated negative sensory attributes. Nonetheless, increased DHA has been linked to promising results in animal growth, fertility,immunity and bone strength in both pigs and poultry. These findings suggest that feeding DHA-rich ingredients to mono-gastric can enrich human diets as well as providing additional benefits to the animal.

关键词： DHA Microalgae Performance Anti-oxidant

EVOKE： A VALUE-DRIVEN CONCEPT SELECTION METHOD FOR EARLY SYSTEM DESIGN

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Journal of Systems Science and Systems Engineering 2018年第1期27卷 46-77页

作者： Marco Bertoni Alessandro Bertoni Ola Isaksson GKN Aerospace Sweden ab Trollhättan Sweden

The development of new technologically advanced products requires the contribution from a range of skills and disciplines, which are often difficult to fred within a single company or organization. Requirements establishment practices in Systems Engineering （SE）, while ensuring coordination of activities and tasks across the supply network, fall short when it comes to facilitate knowledge sharing and negotiation during early system design. Empirical observations show that when system-level requirements are not available or not mature enough, engineers dealing with the development of long lead-time sub-systems tend to target local optima, rather than opening up the design space. This phenomenon causes design teams to generate solutions that do not embody the best possible configuration for the overall system. The aim of this paper is to show how methodologies for value-driven design may address this issue, facilitating early stage design iterations and the resolution of early stage design trade-offs. The paper describes how such methodologies may help gathering and dispatching relevant knowledge about the ＇design intent＇ of a system to the cross-functional engineering teams, so to facilitate a more concurrent process for requirement elicitation in SE. The paper also describes EVOKE （Early Value Oriented design exploration with KnowledgE maturity）, a concept selection method that allows benchmarking design options at sub-system level on the base of value-related information communicated by the system integrators. The use of EVOKE is exemplified in an industrial case study related to the design of an aero-engine component. EVOKE＇s ability to raise awareness on the value contribution of early stage design concepts in the SE process has been further verified with industrial practitioners in ad-hoc design episodes.

关键词： Requirements elicitation concept selection systems engineering value-driven design,decision-making knowledge maturity

Antimicrobial usage and resistance in beef production

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Journal of Animal Science and Biotechnology 2017年第2期8卷 249-270页

作者： Andrew Cameron Tim A.McAllister Faculty of Veterinary Medicine University of CalgaryCalgaryABCanada Agriculture and Agri-Food Canada LethbridgeABCanada

Antimicrobials are critical to contemporary high-intensity beef production. Many different antimicrobials are approved for beef cattle, and are used judiciously for animal welfare, and controversially, to promote growth and feed efficiency. Antimicrobial administration provides a powerful selective pressure that acts on the microbial community, selecting for resistance gene determinants and antimicrobial-resistant bacteria resident in the bovine flora. The bovine microbiota includes many harmless bacteria, but also opportunistic pathogens that may acquire and propagate resistance genes within the microbial community via horizontal gene transfer. Antimicrobial-resistant bovine pathogens can also complicate the prevention and treatment of infectious diseases in beef feedlots,threatening the efficiency of the beef production system. Likewise, the transmission of antimicrobial resistance genes to bovine-associated human pathogens is a potential public health concern. This review outlines current antimicrobial use practices pertaining to beef production, and explores the frequency of antimicrobial resistance in major bovine pathogens. The effect of antimicrobials on the composition of the bovine microbiota is examined, as are the effects on the beef production resistome. Antimicrobial resistance is further explored within the context of the wider beef production continuum, with emphasis on antimicrobial resistance genes in the food chain, and risk to the human population.

关键词： Antibiotics Antimicrobial resistance Antimicrobial usage Beef production Bovine pathogens Bovine microbiota Cattle Enteropathogens Fecal bacteria Resistome

Real-time performance of DAE and ODE based estimators evaluated on a diesel engine

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Science China(Information Sciences) 2018年第7期61卷 27-39页

作者： Erik H?CKERDAL Erik FRISK Lars ERIKSSON Scania CV ab Vehicular Systems Link?ping University

Computation and sampling time requirements for real-time implementation of observers is studied. A common procedure for state estimation and observer design is to have a system model in continuous time that is converted to sampled time with Euler forward method and then the observer is designed and implemented in sampled time in the real time system. When considering state estimation in real time control systems for production there are often limited computational resources. This becomes especially apparent when designing observers for stiff systems since the discretized implementation requires small step lengths to ensure stability. One way to reduce the computational burden, is to reduce the model stiffness by approximating the fast dynamics with instantaneous relations, transforming an ordinary differential equations(ODE)model into a differential algebraic equation(DAE) model. Performance and sampling frequency limitations for extended Kalman filter(EKF)'s based on both the original ODE model and the reduced DAE model are here analyzed and compared for an industrial system. Furthermore, the effect of using backward Euler instead of forward Euler when discretizing the continuous time model is also analyzed. The ideas are evaluated using measurement data from a diesel engine. The engine is equipped with throttle, exhaust gas recirculation(EGR), and variable geometry turbines(VGT) and the stiff model dynamics arise as a consequence of the throttle between two control volumes in the air intake system. The process of simplifying and modifying the stiff ODE model to a DAE model is also discussed. The analysis of the computational effort shows that even though the ODE, for each time-update, is less computationally demanding than the resulting DAE, an EKF based on the DAE model achieves better estimation performance than one based on the ODE with less computational effort. The main gain with the DAE based EKF is that it allows increased step lengths without degrading the

关键词： estimation learning DAE ODE EKF observability real-time

Seismic response of tall building considering soil-pile-structure interaction

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Earthquake Engineering and Engineering Vibration 2002年第1期1卷 57-64页

作者： Han Yingcai Fluor Canada Ltd.,Calgary,ab,Canada Ph.D.,Principal Engineering Specialist Fluor Canada Ltd. Calgary AB Canada

The seismic behavior of tall buildings can he greatly affected by non-linear soil-pile interaction during strong *** this study a 20-storey building is examined as a typical structure supported on a pile foundation for different conditions:(1) rigid base,*** deformation in the foundation:(2) linear soil-pile system;and (3) nonlinear soil-pile system. The effects of pile foundation displacements on the behavior of tall building are investigated,and compared with the behavior of buildings supported on shallow *** a model of non-reflective boundary between the near field and far field, Novak's method of soil-pile interaction is *** computation method for vibration of pile foundations and DYNAN computer program are introduced comprehensively.A series of dynamic experiments have been done on full-scale piles, including single pile and group,linear vibration and nonlinear vibration,to verify the validity of boundary zone model.

关键词： dynamic soil-pile-structure interaction soil dynamics structural dynamics nonlinear vibration seismic response of tall building

A systematic machine learning method for reservoir identification and production prediction

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Petroleum Science 2023年第1期20卷 295-308页

作者： Wei Liu Zhangxin Chen Yuan Hu Liuyang Xu Department of Chemical and Petroleum Engineering University of CalgaryABCanada Rockeast Energy Ltd. CalgaryABCanada Jilin Oilfield CNPCChangchunJilin130000China

Reservoir identification and production prediction are two of the most important tasks in petroleum exploration and *** learning(ML)methods are used for petroleum-related studies,but have not been applied to reservoir identification and production prediction based on reservoir *** forecasting studies are typically based on overall reservoir thickness and lack accuracy when reservoirs contain a water or dry layer without oil *** this paper,a systematic ML method was developed using classification models for reservoir identification,and regression models for production *** production models are based on the reservoir identification *** realize the reservoir identification,seven optimized ML methods were used:four typical single ML methods and three ensemble ML *** methods classify the reservoir into five types of layers:water,dry and three levels of oil(I oil layer,II oil layer,III oil layer).The validation and test results of these seven optimized ML methods suggest the three ensemble methods perform better than the four single ML methods in reservoir *** XGBoost produced the model with the highest accuracy;up to 99%.The effective thickness of I and II oil layers determined during the reservoir identification was fed into the models for predicting *** thickness considers the distribution of the water and the oil resulting in a more reasonable production prediction compared to predictions based on the overall reservoir *** validate the superiority of the ML methods,reference models using overall reservoir thickness were built for *** models based on effective thickness outperformed the reference models in every evaluation *** prediction accuracy of the ML models using effective thickness were 10%higher than that of reference *** the personal error or data distortion existing in traditional methods,this novel system realizes r

关键词： Reservoir identification Production prediction Machine learning Ensemble method