摘要:

Hydrologic variables such as available flow for electrical generation and its time distribution, together with flood magnitudes, represent the basis for evaluation of potential hydro sites. Economic viability, especially for small-scale hydro sites is very sensitive to these basic hydrologic variables. Unfortunately, many potential small-scale hydro sites are located on ungauged streams and often the cost of deriving the necessary site specific hydrologic information for design is prohibitive in relation to overall project costs. Therefore, regional techniques have been developed for evaluating the necessary hydrologic variables at a prefeasibility level for small-scale ungauged sites anywhere in Canada. Studies concerned with developing regional techniques for application to feasibility level evaluations have been completed for Atlantic Canada, British Columbia, and Ontario.The methodology can be used to estimate the flow duration curve and the turbinable flow curve for ungauged streams. Equations relating characteristics of the curves to physiographic and climatic parameters have been derived for eleven regions across Canada. An example demonstrating application of the new methodology is included.Key words: hydroelectric power, small-hydro, regional hydrology, ungauged streams, flow duration curves, turbinable flow curves.

ISSN:0315-1468    

DOI:10.1139/l88-044

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

The development of resource access road route location methods is outlined, leading to the conclusion that there is a need for an access road route location system which uses an overall optimization scheme, facilitates sensitivity analyses, can be implemented on widely available microcomputers, and can be easily integrated into geographic information systems. The algorithm for a microcomputer program, which is designed to fit this specification, is presented and tested with atypical route location problem.Key words: access roads, resource roads, route location, dynamic programming, microcomputers, optimization.

ISSN:0315-1468    

DOI:10.1139/l88-045

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

The durability of concrete to freeze-thaw cycles is dependent upon the existence of an adequate air-void system. There are very few studies on the air-void system of field concretes. Laboratory tests have proven that the air content measurement on the fresh concrete is not sufficient to judge the aptitude of the air-void system to protect the concrete from frost damage.This paper is a comparison of the air-void systems of field concretes produced in either a conventional plant or a mobile unit the use of which is becoming more and more frequent. The concretes produced in the conventional plant generally had sufficient air-void systems for air contents in the usual range (5–7%). The mobile unit showed that a slightly higher air content (8%) was needed to produce an adequate air-void system.Key words: concrete, mobile concrete-mixer, air-void systems, air-entraining agent, spacing factor, surface area, air content.

ISSN:0315-1468    

DOI:10.1139/l88-046

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

A model for nitrogen concentrations in running waters has been developed and associated with the hydrological model CEQUEAU. The model allows the simulation of total nitrogen concentrations at any point in a watershed during various hydrological event. The catchment area is first subdivided into discrete elements; each element is associated with a production function which quantifies the accumulation of nitrogen at the soil–atmosphere interface. Supplementary functions describe the transformations of nitrogen species in the soil and the transfer of the nitrogen load towards the hydrographic system by runoff (caused by rain and (or) snowmelt), and the transport of the different nitrogen compounds downstream. Another function is used to represent the in-stream transformation. Nitrogen data inputs to be modeled are those from precipitation dry deposition, diffuse sources due to agricultural practices, and industrial point sources. The model was applied to the Sainte-Anne River, Québec (catchment area, 2700 km2) in order to reproduce the observed nitrogen concentrations for 1978, 1979, and 1980. Model performance was judged to be promising and it is proposed to validate the model by the simulation of nitrogen concentration on the other rivers for which land use and industrial activity are well documented.Key words: modeling, river, nitrogen, supply, runoff, seepage, drainage.

ISSN:0315-1468    

DOI:10.1139/l88-047

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Environmental indices are useful as a means of communication between governmental control agencies and the general public. While air quality indices are broadly used, water quality indices have found little practical application. The multiplicity of parameters necessary to describe water quality (coliforms, BOD, toxicants, nutrients) renders the public perception of pollution unclear.The present study proposes a new local index for the evaluation of effluent impacts on a receiving water body; this index makes use of linear weighting functions calculated on the differences between the upstream and downstream measurements of parameters which are affected by specific effluents. The procedure ranks each parameter value with regard to the maximum and minimum values observed before and after the outfall. For this reason, the resulting values are very sensitive to local perturbations. Linear characteristics of the index structure allow simple conversion from local databases to broader ones, thus allowing the measure of the cumulative impacts downstream. This index also allows the comparative rating of the water quality through time, if the effluent is subjected to some intervention. As such, it can also contribute to the environmental follow-up of a sanitation program.If a hydrological basin is equipped with a monitoring network, the proposed methodology permits the use of the resulting global database to quantify relative impacts of different effluents, and thus allows a hierarchical classification of the effluents to be treated according to priority.The proposed impact index has been tested with water quality data obtained during one year on a bi-weekly basis upstream and downstream from the untreated sewage outfall of Sainte-Anne de la Pérade (Portneuf, Province of Québec). The computed index as a whole is more sensitive to changes in water quality than individual parameters. External factors such as river flow and temperature do not significantly affect the values of the index.Key words: index, quality, river, impact, environment. [Journal translation]

ISSN:0315-1468    

DOI:10.1139/l88-048

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Three laboratory model anaerobic fixed film reactors, AFFR-A, B, and C, fed by a pretreated leachate, were monitored at 35 ± 5 °C for 10 months to estimate the effects of different concentrations and the forms of phosphate (ortho, organic, or condensed) on performances at 1.2–1.8 g COD/(d∙L) of reactor volume. Ortho phosphate (Na3PO4) supplement was added to the feed of AFFR-A, organic phosphate (sodium glycerophosphate: C3H7Na2O6P∙5H2O) to AFFR-B, and condensed phosphate (Na4P2O7) to AFFR-C at a feed COD/P value of about 6100 for 23 weeks (Phase I). When no PO4deficiency was observed, the value was increased to 7700 in reactors A and B, but the PO4supplement was terminated for reactor C, resulting in a value of 64 300 (Phase II). The average COD of C effluent was 599 mg/L as compared to 451 and 442 mg/L for reactors A and B, respectively, suggesting that a COD/P of 64 300 was too high. During Phase III, the COD/P ratios were changed in reactors A, B, and C, respectively, to 10 200, 15 200, and 34 300. The results indicate that the "optimal" ratio of COD/P lies perhaps between 15 000 and 34 300. Anaerobes did not prefer any one form of PO4over the other two.Key words: anaerobic treatment, phosphate requirement, ortho phosphate, condensed phosphate, organic phosphate, leachate treatment, fixed film reac

ISSN:0315-1468    

DOI:10.1139/l88-049

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Not Available

ISSN:0315-1468    

DOI:10.1139/l88-050

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Complex frequencies and mode shapes are evaluated and presented for a guyed vertical axis wind turbine to detect any dynamic instability for a given speed of rotation. The equations of motion are developed in the rotating system of axes of the rotor to eliminate the time dependent terms. These equations take into account gyroscopic effects by evaluating the Coriolis and Circulatory (softening) matrices. The guys are replaced by nonlinear springs. The geometric stiffness matrix is also considered by performing a nonlinear static analysis that includes centrifugal effects and gravity loads, as well as compression from the vertical component of the guys. A reduction of the dynamic degrees of freedom is performed using the Rayleigh–Ritz technique. The complex frequencies and mode shapes are obtained using the QR algorithm. A program developed on a microcomputer was used to evaluate the dynamic instabilities of the ÉOLE Project. These results are described in the following paper.Key words: Vertical axis wind turbines, guys, complex frequencies, complex mode shapes, centrifugal forces, Coriolis forces, numerical software.

ISSN:0315-1468    

DOI:10.1139/l88-051

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

The dynamic behaviour of the vertical axis wind turbine of the ÉOLE Project is examined using a special purpose program developed for extracting the complex frequencies and mode shapes of the structure. The precise evaluation of the frequencies is an important step in the design process, to detect any dynamic instabilities of the rotor for a given speed. Gyroscopic effects and geometric nonlinearities due to centrifugal and gravity forces as well as the vertical compression due to the tension of the guys are also considered. Nonlinear behaviour of the guys is also accounted for. The influence of the variation in the stiffness of the guys on the dynamic behaviour is examined specifically for the ÉOLE Project. Results indicate that this effect is not important if the initial tension in the guy is high.Key words: Vertical axis wind turbines, guys, complex frequencies, complex mode shapes, centrifugal forces, Coriolis forces, Campbell diagrams, numerical software.

ISSN:0315-1468    

DOI:10.1139/l88-052

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

The seismic loading provisions included in the 1985 edition of the National Building Code of Canada simulate the dynamic response of structures using a seismic response factor, which has three branches depending upon the relationship between the velocity-related seismic zone Zvand the acceleration-related zone Za. This paper utilizes three ensembles of actual seismic strong motion records to evaluate the seismic response factor; each ensemble has acceleration/velocity ratios corresponding to one of the three branches of the seismic response factor. These strong motion time histories are used as input to relatively simple elastic models of frame and wall structures in order to obtain dynamic seismic response factors. The comparison of these dynamic factors with those specified in the NBCC 1985 indicates that the code factors are generally quite satisfactory, with the exception of the case of frame structures with low fundamental periods located such that Zais two zones higher than Zv. The paper references several other investigations that produce similar results. In that instance, it is recommended that the seismic response factor should be increased, particularly if the structure is located on stiff soil rather than on rock.Key words: structures, loading, seismic, code, earthquake, dynamic, elastic, acceleration, velocity, spectra.

ISSN:0315-1468    

DOI:10.1139/l88-053

出版商:NRC Research Press    

年代:1988

数据来源: NRC