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Article

Mete Koken, Ismail Aydin and Akis Sahin

High head gates are commonly used in hydropower plants for flow regulation and emergence closure. Hydrodynamic downpull can be a critical parameter in design of the…

Abstract

Purpose

High head gates are commonly used in hydropower plants for flow regulation and emergence closure. Hydrodynamic downpull can be a critical parameter in design of the lifting mechanism. The purpose of this paper is to show that a simplified two-dimensional (2D) computational fluid dynamics solution can be used in the prediction of the downpull force on the gate lip by comparison of computed results to experimentally measured data.

Design/methodology/approach

In this study, ANSYS FLUENT CFD software was used to obtain 2D numerical solution for the flow field around a generic gate model located in a power intake structure which was previously used in an experimental study. Description of the flow domain, computational grid resolution, requirements on setting appropriate boundary conditions and methodology in describing downpull coefficient are discussed. Total number of 245 simulations for variable gate lip geometry and gate openings were run. The downpull coefficient evaluated from the computed pressure field as function of gate opening and lip angle are compared with the experimental results.

Findings

The computed downpull coefficient agrees well with the previous experimental results, except one gate with small lip angle where a separation bubble forms along the lip, which is responsible from this deviation. It is observed that three-dimensional (3D) effects are confined to the large gate openings where downpull is minimum or even reversed.

Research limitations/implications

In large gate openings, three dimensionality of the flow around gate slots plays an important role and departure from 2D solutions become more pronounced. In that case, one might need to perform a 3D solution instead.

Practical implications

This paper presents a very fast and accurate way to predict downpull force on high head gates in the absence of experimental data.

Originality/value

An extensive amount of simulations are run within the scope of this study. It is shown that knowing its limitations, 2D numerical models can be used to calculate downpull for a wide range of gate openings without the need of expensive experimental models.

Details

Engineering Computations, vol. 34 no. 4
Type: Research Article
ISSN: 0264-4401

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Article

George K. Chacko

Develops an original 12‐step management of technology protocol and applies it to 51 applications which range from Du Pont’s failure in Nylon to the Single Online Trade…

Abstract

Develops an original 12‐step management of technology protocol and applies it to 51 applications which range from Du Pont’s failure in Nylon to the Single Online Trade Exchange for Auto Parts procurement by GM, Ford, Daimler‐Chrysler and Renault‐Nissan. Provides many case studies with regards to the adoption of technology and describes seven chief technology officer characteristics. Discusses common errors when companies invest in technology and considers the probabilities of success. Provides 175 questions and answers to reinforce the concepts introduced. States that this substantial journal is aimed primarily at the present and potential chief technology officer to assist their survival and success in national and international markets.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 14 no. 2/3
Type: Research Article
ISSN: 1355-5855

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Article

Yuan Ding, TongChun Li, LanHao Zhao, MinZhe Zhou and ChaoNing Lin

Multi-level intake structures are used to take the surface water of reservoirs. The changed boundary conditions will certainly make the water hammer phenomenon more…

Abstract

Purpose

Multi-level intake structures are used to take the surface water of reservoirs. The changed boundary conditions will certainly make the water hammer phenomenon more complicated. This paper aims to find out the influence and law of the water hammer pressure after setting the stop log gates.

Design/methodology/approach

The authors use the computational fluid dynamics method with the adaptive grid technology to stimulate the water hammer phenomenon of the multi-level intake hydropower station. In the analysis, we set several different heights of stop log gates and two representative times in the starting up and shutdown processes to reflect the impact of multi-level intake structures.

Findings

The authors find that the setting of the stop log gates will reduce the pressure during the normal operation and will increase the period and amplitude of the water hammer wave, but will not necessarily increase the maximum water hammer pressure during the shutdown process. The relationship between the height of the stop log gates and the amplitude of the water hammer wave is affected by the shutdown time. After setting stop log gates, the depression depth and wave height of the water level in front of the dam increase when the load changes.

Originality/value

The authors study in this paper the water pressure of the multi-level intake hydropower station that has never been studied before and obtain some laws.

Details

Engineering Computations, vol. 36 no. 3
Type: Research Article
ISSN: 0264-4401

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Article

Li‐teh Sun

Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the…

Abstract

Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American preemptive invasion and occupation of Afghanistan and Iraq and the subsequent prisoner abuse, such an existence seems to be farther and farther away from reality. The purpose of this work is to stop this dangerous trend by promoting justice, love, and peace through a change of the paradigm that is inconsistent with justice, love, and peace. The strong paradigm that created the strong nation like the U.S. and the strong man like George W. Bush have been the culprit, rather than the contributor, of the above three universal ideals. Thus, rather than justice, love, and peace, the strong paradigm resulted in in justice, hatred, and violence. In order to remove these three and related evils, what the world needs in the beginning of the third millenium is the weak paradigm. Through the acceptance of the latter paradigm, the golden mean or middle paradigm can be formulated, which is a synergy of the weak and the strong paradigm. In order to understand properly the meaning of these paradigms, however, some digression appears necessary.

Details

International Journal of Sociology and Social Policy, vol. 25 no. 4/5
Type: Research Article
ISSN: 0144-333X

Keywords

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Article

George K. Chacko

Gives an in depth view of the strategies pursued by the world’s leading chief executive officers in an attempt to provide guidance to new chief executives of today…

Abstract

Gives an in depth view of the strategies pursued by the world’s leading chief executive officers in an attempt to provide guidance to new chief executives of today. Considers the marketing strategies employed, together with the organizational structures used and looks at the universal concepts that can be applied to any product. Uses anecdotal evidence to formulate a number of theories which can be used to compare your company with the best in the world. Presents initial survival strategies and then looks at ways companies can broaden their boundaries through manipulation and choice. Covers a huge variety of case studies and examples together with a substantial question and answer section.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 11 no. 2/3
Type: Research Article
ISSN: 1355-5855

Keywords

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Article

Bill Gates, Chairman and CEO of Microsoft Corporation, holds that the Information Highway does not exist, and that it would not be available to most US homes for at least…

Abstract

Bill Gates, Chairman and CEO of Microsoft Corporation, holds that the Information Highway does not exist, and that it would not be available to most US homes for at least a decade. Where one of the most knowledgeable authorities on Information Technology (IT) fears to tread, wordsmiths rush in. Don Tapscott, for one, affirms that the dominant economic sector in the Digital Economy is being created by three converging industries and that convergence is becoming the basis of all sectors. Convergence in mathematics is the progressive approach of a function to a pre‐specified value(s). If a thousand coins are tossed, the number of heads in a single toss could vary from 0 head to 1,000 heads. If the coins are not loaded, the number of heads in each toss could be high or low, but in successive tosses, the fraction of heads will approach closer and closer to 0.5 (Converge( as n, the number of tosses, tends to infinity. Tapscott provides no measures of convergence — conceptual, theoretical, empirical, or operational — without which we would not know if convergence has indeed descended upon us; what is more, we have no idea if we are/are not progressing toward the consummation of convergence upon which Tapscott's Digital Economy is predicated. Even more damaging to the Tapscott thesis of “three converging industries … becoming the basis of all sectors” is the conspicuous absence of any movement toward convergence on the part of the leading firms in the three industries. On the contrary, we find that each of them is racing on its own Divergent path of high and higher tech. Both the CEOs of IBM and Microsoft believe that high‐speed, high‐bandwidth is the future; and both swear by the Internet. But they race toward the Information Super Highway in their own separate, individual tracks. Product and service differentiation are the rule of the day; not standardization. Open architecture is a distant dream. Turning from the giant of hardware (IBM) and of software (Microsoft) to the giant of communications (AT&T), what is the story of convergence? AT&T entered the field of computers under the MFJ [Modified Final Judgment] of 1982. It beat a decisive path of retreat from convergence five years later by breaking up on January 1, 1997, into three communications and computer companies. How can the 3Cs converge? Not by their own volition. It is clear from the strategies of IBM, Microsoft, and AT&T that each of them is racing on its own path of high and higher tech. There is little evidence of convergence by default. If we want to achieve convergence by design, we have to emulate Hannibal. Facing the European Alps with his army of elephants, Hannibal said: “I will either find a way or invent one.” We will have to invent an appropriate methodology of convergence.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 9 no. 1/2
Type: Research Article
ISSN: 1355-5855

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Article

V. Jaiganesh and K. Prakasan

The purpose of this work is to visualize the flow behaviour in critical sections of a pressurized gating system.

Abstract

Purpose

The purpose of this work is to visualize the flow behaviour in critical sections of a pressurized gating system.

Design/methodology/approach

The investigation was carried out using water models of gating system that were designed, invoking the principles of similitude. Water was used as the filling medium, and the manner of flow through various sections of the gating system and the cavity was recorded with a high-speed camera capable of capturing images up to 10,000 frames per second. This was followed by an analysis of the results obtained from each phase. Finally, computer simulations of flow were carried out using commercial software. The manner of filling as observed during experiments and that during simulation were compared so as to draw some useful conclusions on the utility of flow visualization using water models and the capability of software to predict the filling pattern during casting process. It was understood that water models are powerful aids for understanding the intricacies of flow through critical sections of the gating systems.

Findings

It was observed that water models are a reliable indicator of the mould-filling process. Further, substantial differences in the filling pattern were observed between water model experiments and filling simulation using commercial software.

Research limitations/implications

The findings are limited to horizontal plate-type castings. Also, the influence of surface roughness in the flow through the runner is not considered.

Originality/value

This work facilitates understanding of the importance of flow visualization on the quality and reliability of castings.

Details

Journal of Engineering, Design and Technology, vol. 14 no. 3
Type: Research Article
ISSN: 1726-0531

Keywords

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Article

Li‐teh Sun

Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the…

Abstract

Man has been seeking an ideal existence for a very long time. In this existence, justice, love, and peace are no longer words, but actual experiences. How ever, with the American preemptive invasion and occupation of Afghanistan and Iraq and the subsequent prisoner abuse, such an existence seems to be farther and farther away from reality. The purpose of this work is to stop this dangerous trend by promoting justice, love, and peace through a change of the paradigm that is inconsistent with justice, love, and peace. The strong paradigm that created the strong nation like the U.S. and the strong man like George W. Bush have been the culprit, rather than the contributor, of the above three universal ideals. Thus, rather than justice, love, and peace, the strong paradigm resulted in in justice, hatred, and violence. In order to remove these three and related evils, what the world needs in the beginning of the third millenium is the weak paradigm. Through the acceptance of the latter paradigm, the golden mean or middle paradigm can be formulated, which is a synergy of the weak and the strong paradigm. In order to understand properly the meaning of these paradigms, however, some digression appears necessary.

Details

International Journal of Sociology and Social Policy, vol. 25 no. 6/7
Type: Research Article
ISSN: 0144-333X

Keywords

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Article

Soma Hewa

Ponders on whether Abraham Flexner was responsible for the change in medical education in North America in the early 20th century, owing to his report of 1910. Tries to…

Abstract

Ponders on whether Abraham Flexner was responsible for the change in medical education in North America in the early 20th century, owing to his report of 1910. Tries to demonstrate that medical education in the USA was part of a greater whole of major changes at that time. Concludes, though there was a philanthropic influence, Flexner (who refused to accept credit for change) was not the father of the medical reform plan.

Details

International Journal of Sociology and Social Policy, vol. 22 no. 11/12
Type: Research Article
ISSN: 0144-333X

Keywords

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Article

Symeon Christodoulou

The purpose of the paper is to perform bid mark‐up optimisation through the use of artificial neural networks (ANN) and a metric of the selected bid mark‐up's derived…

Abstract

Purpose

The purpose of the paper is to perform bid mark‐up optimisation through the use of artificial neural networks (ANN) and a metric of the selected bid mark‐up's derived entropy. The scope is to provide an alternative, entropy‐based method for bid mark‐up optimisation that improves on the analytical models of Friedman and Gates.

Design/methodology/approach

The proposed method enables the incorporation of bid parameters through the use of ANN's pattern recognition capabilities and the integration of these parameters with a mark‐up selection process that relies on the entropy produced by possible mark‐up values. The entropy metric used is the product of the probability of winning over the bidder's competitors multiplied by the natural logarithm of the inverse of this probability.

Findings

The case study results show that the proposed entropy‐based bidding model compares favourably with the prevailing competitive bidding models of Friedman and Gates, resulting in higher optimisation with regards to the number of jobs won, the monetary value of contracts awarded and the value of “money left on the table”. Furthermore, the method allows for the incorporation of several objective and subjective bid parameters, in contrast to Friedman's and Gates's models, which are based solely on the bid mark‐up history of a bidder's competitors.

Research limitations/implications

While the proposed method is a useful tool for the selection of optimal bid mark‐up values, it requires historical data on the bidding behaviour of key competitors, much like the classic bidding models of Friedman and Gates.

Originality/value

The method is suitable for quantifying objective and subjective competitive bidding parameters and for optimising bid mark‐up values.

Details

Engineering, Construction and Architectural Management, vol. 17 no. 4
Type: Research Article
ISSN: 0969-9988

Keywords

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