Tetreault P.R.,Genivar Inc. |
El-Geneidy A.M.,McGill University
Transportation Research Part A: Policy and Practice | Year: 2010
In recent years, several transit agencies have been trying to be more competitive with the automobile to attract choice riders. Transit agencies can only be competitive if they can provide services that are reliable, have a short access and egress time, and have run times that are comparable to automobiles. Several transit agencies try to be competitive through offering faster service, such as limited-stop (express) bus service. This study uses AVL and APC data, in addition to a disaggregate data obtained from a travel behavior survey, to select stops and estimate run times for a new limited-stop service that will run parallel to a heavily used bus route (67 Saint-Michel) in Montréal, Canada. Three different scenarios are developed based on theory and practice to select stops to be incorporated in the new limited service. The time savings for each scenario are then evaluated as a range and a fourth scenario is developed. A limited-stop service is recommended based on selecting stops serving both directions of the route, major activity points and stop spacing. This study shows that implementing a limited-stop service would yield substantial time savings for both, the new limited service and the existing regular service running in parallel. © 2010 Elsevier Ltd.
Sun J.,Genivar Inc. |
Lovegrove G.,University of British Columbia
Canadian Journal of Civil Engineering | Year: 2013
The Canada Mortgage and Housing Corporation (CMHC) has been researching a sustainable community development pattern - the Fused Grid road network. This paper reports on research to compare the road safety level of the Fused Grid with four other networks, including: traditional (1) grid and (2) culs-de-sac patterns, and, recently developed (3) 3-way offset and (4) Dutch sustainable road safety (SRS) patterns. Community-based, macro-level collision prediction models were developed and applied with data from Vancouver, Ottawa, and Victoria. The research used standard experimental design methods, including: control-trigger variables, sensitivity analysis, and cross-sectional analysis. Statistically significant results were obtained, and suggested that neighbourhoods built following CMHC's Fused Grid road network pattern would realize a 30 to 60% higher level of road safety than the commonly-used grid and culs-de-sac patterns, and a level of safety comparable to the 3-way offset pattern. Further research topics were recommended.
Gerla P.J.,University of North Dakota |
Sharif M.U.,University of Arkansas |
Korom S.F.,Genivar Inc.
Environmental Earth Sciences | Year: 2011
Selenium (Se) is essential in the human diet, but has a low threshold for toxic concentration. It is recommended that nutrients such as Se should be consumed through foods as part of a normal diet. Se concentrations in crops and meat depend on the amount of labile Se in the soil where crops and forage are grown. Therefore, managing agriculture for optimal Se in grain crops and forage requires an understanding of the distribution and mobility of Se. Elevated concentrations of Se occur in waters, soils, and forage 120 km west of Pierre in west central South Dakota, USA. The research site lies in an elevated, dissected plain where soils developed on gently dipping Pierre Shale. Soils were sampled along catena transects and waters collected from soil, ponds, and shallow borings in areas of known elevated forage and crop Se. Soil extracts from saturatedpaste extraction and acid (aqua regia and hydrofluoric acid) extraction were analyzed. Selenate was the dominant Se species in both acid and saturated-paste extracts; selenite and organic Se were below detection (<0.2 ppb) in the same soil extracts. On average, 98% of soil Se was not water-soluble. The distribution of total Se shows much less spatial variation than water-soluble Se in the areas sampled. Se shows correlation with organic carbon in soils and waters, suggesting its association with organic carbon. Ca shows some correlation to Se in acid extracts, but not in saturated-paste extracts or in waters. Total Se shows no significant correlation to Na, Mg, and total S in the soils. Se in saturated-paste extracts and water samples shows good correlations with Na, Mg, and SO 4, suggesting that evaporitic Na-Mg-sulfate minerals may temporarily concentrate water-soluble Se in shallow soils. The dissolution and precipitation of these Na-Mg-sulfate salts together with pH and oxidation-reduction conditions apparently control water-soluble Se distribution and mobilization in shallow subsurface environments. © Springer-Verlag 2010.
Croteau A.,Genivar Inc. |
Nastev M.,Geological Survey of Canada |
Lefebvre R.,INRS - Institute National de la Recherche Scientifique
Canadian Water Resources Journal | Year: 2010
The objective of this study was to evaluate groundwater recharge in the Chateauguay River watershed. The Hydrologic Evaluation of Landfill Performance (HELP) model was used to assess daily values of recharge, evapotranspiration and runoff. The study area was divided into a regular grid, 250 m × 250 m, for a total of 47,616 grid elements. The input parameters included soil physical properties, land use, vegetation and climate data. Calibration of HELP was carried out against runoff and baseflow estimates obtained from separation of five river hydrographs. Over a 39 year period, the mean annual recharge rate was estimated at 86 mm, or 9% of the total precipitation. Areas characterized by high water level elevations and unconfined flow conditions were identified as the main recharge areas. Daily estimates show that recharge takes place mainly in spring and fall. Over the observed period, the annual variations of evapotranspiration and runoff were directly related to changes in precipitation, whereas the annual recharge response was subdued, with much lower variations. HELP was also used to assess potential climate change scenarios using data for the driest and most humid years. The mean annual recharge was 51 mm for the driest year and 99 mm for the most humid year. Differences in the spatial distribution of recharge for the predictive scenarios indicate that the areas most sensitive to climate change correspond to the preferential recharge areas. © 2010 Canadian Water Resources Association.
Salvo P.,Genivar Inc.
30th International No-Dig Conference and Exhibition 2012, No-Dig Sao Paulo 2012 | Year: 2012
This paper will present condition assessment tools that were available to the municipal engineers, as well as presenting new condition assessment tools that have become available over the last few years for both the potable water and sewer systems. These new systems are both innovative in nature and give more precise information to the decision makers. The paper will be divided in two distinct sections, the first being the sewer system condition assessment tools (past and present) for gravity sewers and force mains and the second will be for the potable water system condition assessment tools (past and present) for larger transmission pipes and for the secondary distribution pipes. Given that the sewer system is predominately an open system, access to the network is via the existing manhole chambers, with the exception of force mains which require a different approach. In the past and present, conventional CCTV inspection is used frequently. However, over the years, the improvements in the camera technology make CCTV inspections a more accurate tool. In the secondary sewer pipes, we can use a zoom camera to give us a snapshot of the state of the pipe over a short distance, usually 20 to 30 meters. The conventional CCTV cameras will show any defects in the pipe and at the service connection. In the case of an interceptor sewer pipe that has a larger diameter and is usually full of water up to 50%, conventional CCTV does not always work, because in order to see the entire pipe, the cost of by-passing the flow to get a dry pipe is too expensive and time consuming. One technology that has been very successful is the use of a Multi-Sensor Inspection unit that provides CCTV, Sonar, Laser Profiling and H2S readings in one operation. In the case of force mains, new technology exist that will allow detecting if there is a leak or can provide a method of calculating residual thickness of the pipe. In part two we will give a brief overview of the technologies that have been used and are still being used to find leaks and estimate the effectiveness and residual life of a potable water main. These technologies include correlation, geophones, C-Value testing and hydrant flows. Some of the new technologies for potable water mains allow the inspection of the water main without having to depressurize the water system. By doing so, the technology has the capability of seeing, hearing and locating leaks, unaccounted for house connections, unaccounted for valves and changes in direction, to name a few. For larger diameter pipes there are technologies that can provide leak detection using a cable tethered system and some using free flowing devices. This paper will present these tools and their applicability in the potable water network. As part of each section, some case studies will be presented to demonstrate the capability of the technology.
Li L.,Genivar Inc. |
Li L.,Ecole Polytechnique de Montréal |
Li L.,École de Technologie Supérieure of Montreal |
Aubertin M.,Ecole Polytechnique de Montréal
Geomechanics and Geoengineering | Year: 2010
The increasing use of backfill in underground mines requires a proper evaluation of the stress state in and around the filled openings. This is, however, a relatively complex issue due, in part, to the large contrast in strength and stiffness between the backfill material and surrounding rock mass. In recent years, it has been shown that arching theory, based on limit equilibrium analysis, can be used to estimate the stress distribution in backfilled stopes. Nonetheless, many simplifications are involved in such analytical solutions and this affects the precision and significance of the calculated results. In this paper, a previously developed solution is enhanced by introducing the combined effects of non-uniform vertical stress distribution and positive pore water pressure. This leads to a more representative analytical solution, as demonstrated by successful comparisons with numerical simulations. The results indicate that the proposed solution can be used to estimate the effective and total stress state in submerged or partially submerged backfilled stopes with a simple geometry. © 2010 Taylor & Francis.
Todesco G.,Genivar Inc.
ASHRAE Journal | Year: 2010
The innovative design and technologies are required to achieve high performance, low energy building designs suitable for cold climates, which are 50% better than Standard 90.1-2007. Integrated design process (IDP) is adopted to design low energy buildings, which allows designer to take benefit of the synergies existing between building elements and maximize energy saving while minimizing incremental costs. The low energy design could achieve potential savings as high as 59% with the use of technologies including efficient fluorescent lighting design with a low LPD of 0.6 W/ft2, daylighting controls, effective cooling plants and alternate HVAC design such as DOAS and chilled ceiling system. The efficient lighting design and innovative variable speed, frictionless, centrifugal chiller can achieve an IPLV of 0.45 and a full load performance of 0.5 kW/ton. The implementation of renewable technologies such as photovoltaic (PV) collectors on the roof ensures the reduction in the consumption of energy of 175,000 kWh/year.
Poulin J.-F.,University of Moncton |
Poulin J.-F.,Genivar Inc. |
Villard M.-A.,University of Moncton
Landscape Ecology | Year: 2011
Conservation strategies should be based on a solid understanding of processes underlying species response to landscape change. In forests fragmented by agriculture, elevated nest predation rates have been reported in many forest bird species, especially near edges. In intensively-managed forest landscapes, timber harvesting might also be associated with negative edge effects or broader "context" effects on some species when the matrix provides additional resources to their major nest predators. In this study, we hypothesized that proximity to a forest edge and proportion of cone-producing plantations will increase nest predation risk in fragments of relatively undisturbed forest. We focused on the Brown Creeper (Certhia americana), an indicator species of late-seral forests. We compared habitat configuration and composition at four spatial scales (0.14, 0.5, 1 and 2 km) around 54 nests and related daily nest survival rate to the distance to the nearest forest edge, mean patch size of late-seral forest (r = 141 m), proportion of non-forested lands (r = 141 m), density of maintained roads (r = 1 km), proportion of cone-producing spruce plantations (r = 2 km), and year. The best model included distance to the nearest edge and proportion of cone-producing plantations. Distance of nests to the nearest edge was the best individual predictor of daily nest survival. A larger sample of nests showed a significant threshold in distance to the nearest forest edge; nests located at least 100 m away were more likely to fledge young. These results suggest that even in managed forest landscapes, matrix effects can be important and some bird species may exhibit negative edge effects. © 2011 Springer Science+Business Media B.V.
Poulin J.-F.,University of Moncton |
Poulin J.-F.,Genivar Inc. |
Villard M.-A.,University of Moncton |
Hache S.,University of Moncton
Ecoscience | Year: 2010
The brown creeper (Certhia americana) was recently identified as one of the forest bird species most sensitive to partial harvesting in North America. However, the processes underlying this sensitivity are poorly known. In this study, we quantified the immediate, post-treatment demographic response of this species to experimental selection harvesting in plots of northern hardwood forest in northwestern New Brunswick, Canada. We mapped individual detections and nest locations in 5 pairs (1 control and 1 treatment) of 25-ha plots in the first 2 y after single-tree selection harvesting. Linear mixed models with site and landscape context as random effects showed a significant negative effect of treatment on nest density and seasonal reproductive success. The density of large-diameter trees (≥ 30 cm dbh) was significantly lower in treated plots than in controls (mean: 77 versus 112 stems·ha-1), whereas the density of potential nesting substrates (snags with peeling bark) did not decrease significantly following treatment. Hence, the density of suitable foraging substrates may represent a limiting factor for both nest density and reproductive success, and partial harvesting may not be compatible with the persistence of breeding populations of brown creeper. Patches of untreated forest should be maintained in managed forest landscapes at all times for this and other taxa requiring old forest conditions.