bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic enhancement of pearl millet and sorghum for the semi-arid tropics of Asia and Africa
Authors: Rai K N , Murty D S , Andrews D J , Bramel-Cox P J
Published: April 2011

Sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R. Br.), ranking fifth and sixth in global cereal hectarage, respectively, are the most important coarse-grain cereals in the semi-arid tropical regions of Asia and Africa. Pearl millet displays better adaptation to and is grown in relatively more marginal environments than sorghum. Under subsistence farming conditions, both crops have low grain yields (0.5-0.7 t·ha-1 for pearl millet and 0.7-0.9 t·ha-1 for sorghum), although improved hybrid cultivars give 3-4 t·ha-1 of realizable grain yields in better-endowed environments. African germplasm, especially Zera Zera sorghums from the Sudan-Ethiopian border in eastern Africa and Iniari pearl millets from the Togo - Ghana - Benin - Burkina Faso region of western Africa, has proved most useful for the genetic improvement of these crops. The greatest impact of improved cultivars (mostly hybrids) has occurred in India, where the area under high-yielding varieties (HYVs) increased from 6% for pearl millet and 3% for sorghum in the triennium 1968-1970 to 53% for pearl millet and 54% for sorghum in the triennium 1992-1994. During the same period, productivity of both crops increased by 59%, which is attributable to both genetic improvement and management factors. HYVs have now started to be adopted in some of the African countries as well (e.g., Chad, Cameroon, Botswana, and Zimbabwe for sorghum; Chad, Namibia, Zambia, and Zimbabwe for pearl millet). The availability of vast untapped genetic resources and continuing yield gains indicate that there are good prospects for future genetic improvement in the productivity of these crops, which can be accelerated with the application of biotechnological tools. Sorghum and pearl millet will continue to be important food crops in their traditional semi-arid tropical areas. Sorghum is already an important feed crop in the developed world and pearl millet has the potential to become an even better feed crop, as it has higher protein content and a better amino acid profile than sorghum. The nutritional value of both crops for food and feed use can be further improved by breeding. Also, through genetic enhancement, there exist opportunities for the development of sorghum and pearl millet cultivars suitable for alternative uses in the bakery and beverage industries.Key words: sorghum, Sorghum bicolor, pearl millet, Pennisetum glaucum, genetic enhancement, semi-arid tropics, Asia, Africa, cultivars, impact.
Chromosome-mediated and direct gene transfers in wheat
Authors: Jauhar Prem P , Chibbar Ravindra N
Published: April 2011

Wild grasses, including relatives of wheat, have several desirable characters that can be introduced into both bread wheat and durum wheat. Since current wheat cultivars lack certain traits, for example, resistance to fusarium head blight (scab), related wild grasses may be the only option for useful variability. Wide hybridization of wheat with grasses, coupled with cytogenetic manipulation of the hybrid material, has been instrumental in the genetic improvement of wheat. Chromosome engineering methodologies, based on the manipulation of pairing control mechanisms and induced translocations, have been employed to transfer into wheat specific disease and pest resistance genes from annual (e.g., rye) or perennial (e.g., Thinopyrum spp., Lophopyrum spp., and Agropyron spp.) members of the wheat tribe, Triticeae. The advent of in situ hybridization techniques, for example, fluorescent GISH combined with Giemsa C-banding, has proved immensely useful in characterizing alien chromatin specifying resistance to various pathogens and pests. The use of DNA markers (RAPDs and RFLPs) helps to identify desirable genotypes more precisely and, thereby, facilitates gene transfer into wheat. Such markers may be particularly helpful in monitoring the introgression of alien genes in the wheat genome. In fact, several cultivars, particularly of bread wheat, contain superior traits of alien origin. The development of novel gene-transfer techniques in the past decade that allow direct delivery of DNA into regenerable embryogenic callus of wheat has opened up new avenues of alien-gene transfer into wheat cultivars. Thus, transgenic bread and durum wheats have been produced and methods of gene delivery standardized. The application of transgenic technology has not only yielded herbicide-resistant wheats, but has also helped to improve grain quality by modifying the protein and starch profiles of the grain. These in vitro approaches to gene transfer are developing rapidly, and promise to become an integral part of plant breeding efforts. However, the new biotechnological tools will complement, not replace, conventional plant breeding.Key words: alien-gene transfer, fluorescent GISH, Giemsa banding, homoeologous chromosome pairing, molecular markers, transgenic bread wheat, transgenic durum wheat.
Identification and chromosomal location of a new tandemly repeated DNA in maize
Authors: Chen Chunxian , Yan Huihuang , Zhai Wenxue , Zhu Lihuang , Sun Jingsan
Published: April 2011

Two clones of a new family of tandemly repeated DNA sequences have been isolated from a maize random genomic DNA library. MR68 is 410 bp, representing a monomeric unit and MR77 is 1222 bp, containing three units. The copy number was estimated to be about 3000 per 1C maize genome. Its methylation pattern was also determined. Fluorescent in situ hybridization (FISH) indicates that the sequence is located on the subtelomeric region of the long arm of chromosomes 3 and 6, as well as on the satellite of chromosome 6. Key words: Zea mays, tandemly repeated DNA, satellite DNA, fluorescent in situ hybridization (FISH).
Geographic dimorphism of the wild silkworm, Bombyx mandarina, in the chromosome number and the occurrence of a retroposon-like insertion in the arylphorin gene
Authors: Nakamura T , Banno Y , Nakada T , Nho S K , Xü M K , Ueda K , Kawarabata T , Kawaguchi Y , Koga K
Published: April 2011

Individuals of the wild silkworm, Bombyx mandarina, collected in South Korea (Taegu City) and Japan (Tsushima Islands and Fukuoka City) had the chromosome number of 2n = 54, while those collected in China (Hangzhou City) had the chromosome number of 2n = 56. Analysis by PCR (polymerase chain reaction) showed that the 66-bp-long retroposon-like insertion known in the arylphorin gene was present in the B. mandarina specimens with 2n = 54, but not in those with 2n = 56. Thus, dimorphism in the chromosome number coincided with the occurrence of the insertion. It is likely that the boundary dividing the two geographic B. mandarina populations lies somewhere in the northern part of the Korean Peninsula.Key words: Bombyx mandarina, chromosome dimorphism, arylphorin gene, geographical populations.
Properties of sequence-tagged-site primer sets influencing repeatability
Authors: Vanichanon A , Blake N K , Martin J M , Talbert L E
Published: April 2011

The polymerase chain reaction (PCR) has become a standard procedure in plant genetics, and is the basis for many emerging genomics approaches to mapping and gene identification. One advantage of PCR is that sequence information for primer sets can be exchanged between laboratories, obviating the need for exchange and maintenance of biological materials. Repeatability of primer sets, whereby the same products are amplified in different laboratories using the same primer set, is important to successful exchange and utilization. We have developed several hundred sequence-tagged site (STS) primer sets for wheat and barley. The ability of the primer sets to generate reproducible amplifications in other laboratories has been variable. We wished to empirically determine the properties of the primer sets that most influenced repeatability. A total of 96 primer sets were tested with four genomic DNA samples on each of four thermocyclers. All major bands were repeatable across all four thermocyclers for approximately 50% of the primer sets. Characteristics most often associated with differences in repeatability included primer GC content and 3'-end stability of the primers. The propensity for primer-dimer formation was not a factor in repeatability. Our results provide empirical direction for the development of repeatable primer sets. Key words: STS-PCR primers, wheat, barley.
Microsatellite markers useful throughout the genus Dianthus
Authors: Smulders MJM , Rus-Kortekaas W , Vosman B
Published: April 2011

Using repeats found in sequences from Dianthus species present in the EMBL database, primers for STMS (sequence-tagged microsatellite site) analysis were developed and tested. Five loci were polymorphic and amplified products of sufficient quality in nearly all of the 26 Dianthus species tested, except MS-DINGSTA, which amplified in only one-third of the species. Loci MS-DINMADSBOX and MS-DCDIA30 produced allele series that were mostly two nucleotides (the repeat unit) apart. MS-DCAMCRBSY and MS-DINCARACC also amplified regular series of alleles, but more than two fragments per individual were detected in a number of species. Both loci code for a member of the ACC synthase gene family. The observation that the loci amplified across a wide range of Dianthus species may imply that the different species within the genus are relatively closely related. Alternatively, it may indicate that the regions selected for primer design (some of which are in coding regions) are well conserved. These microsatellites will be useful for the measurement of genetic diversity in natural populations of Dianthus species and the identification of carnation varieties. Key words: SSR, simple sequence repeat, identification, STMS, sequence-tagged microsatellite site.
Inheritance and RAPD tagging of multiple genes for resistance to net blotch in barley
Authors: Molnar S J , James L E , Kasha K J
Published: April 2011

A doubled haploid barley (Hordeum vulgare L.) population that was created from a cross between cultivars 'Léger' and 'CI 9831' was characterized by RAPD (random amplified polymorphic DNA) markers for resistance to isolate WRS857 of Pyrenophora teres Drechs. f. sp. maculata Smedeg., the causal agent of the spot form of net blotch. Resistance, which initially appeared to be conferred by a single gene from the approximate 1:1 (resistant : susceptible) segregation ratio of the doubled-haploid (DH) progeny, was found to be associated with three different genomic regions by RAPD analysis. Of 500 RAPD random primers that were screened against the parents, 195 revealed polymorphic bands, seven showed an association to the resistance in bulks, and these seven markers were mapped to three unlinked genomic regions. Two of these regions, one of which was mapped to chromosome 2, have major resistance genes. The third region has some homology to the chromosome 2 region. This study demonstrates the simultaneous location of markers for more than one gene governing a trait by using RAPD and bulked segregant analysis (BSA).

Key words: net blotch, RAPD markers, bulked segregant analysis, barley, doubled haploids.
Isolation of large terminal sequences of BAC inserts based on double-restriction-enzyme digestion followed by anchored PCR
Authors: Yang Zhong-Nan , Mirkov T Erik
Published: April 2011

Isolation of the terminal portions of genomic DNA cloned in bacterial artificial chromosomes (BACs) is an important step in map-based cloning, and several methods have been developed. Here, we present a new method based on double-restriction-enzyme digestion followed by anchored PCR. BAC DNA was digested with two enzymes: NotI and one of four enzymes (EcoRV, HpaI, StuI, or XmnI) that produce blunt termini. After dephosphorylation, these digestions were ligated to NotI- and EcoRV-digested pMSK, a new cloning vector developed in this work that is derived from pBluescript SK(+). PCR products representing the left- and right-terminal sequences of BAC inserts were obtained using a primer complementary to pMSK and a primer complementary to sequences in either the left arm or the right arm of the BAC vector pBeloBAC11. We have tested this method with 15 different BAC clones, and PCR products representing both the left- and right-terminal sequences have been obtained from all 15 BAC clones. This method is simple, fast, reproducible, and uses the same set of primers for any restriction enzyme used. With some modifications, it can also be used for isolating the terminal portions of genomic DNA cloned in yeast artificial chromosomes and P1-derived artificial chromosomes.

Key words: BAC, anchored PCR, terminal sequence isolation, chromosome walk.
Dynamic characteristics of the Crowchild Trail Bridge
Authors: Ventura Carlos E , Onur Tuna , Tsai Pei-Chin
Published: April 2011

This paper presents the results of a study on the dynamic characteristics of the Crowchild Trail Bridge in Calgary, Alberta. This bridge is currently being monitored by members of the Intelligent Sensing for Innovative Structures Network (ISIS Canada). The effects of various modeling assumptions on the computed dynamic characteristics of the bridge are investigated and discussed in this paper. The dynamic characteristics of the bridge were determined by means of ambient vibration measurements and were used to calibrate a number of computer models developed by four different groups of engineers. The results of this study showed that in order to properly calibrate a model of the bridge for structural dynamic analysis, it is necessary to have not only a good match of experimental and analytical natural frequencies but also a good match of experimental and analytical mode shapes. Improper determination of dynamic characteristics of a bridge using analytical models could lead to erroneous conclusions on its expected behaviour under dynamic loading.Key words: ambient vibration testing, dynamic characteristics, bridge modeling, instrumentation, accelerometers, modal analysis.
Traitement physico-chimique d'une eau souterraine fortement chargée en fer et en manganèse
Authors: Lessard Catherine , Ellis Donald , Sérodes Jean , Bouchard Christian
Published: April 2011

Conventional greensand treatment for the removal of iron and manganese from groundwater is not quite appropriate for waters with a high content of iron and manganese. In this pilot study, different modifications to this process were tested to improve treatment performances for water with a high concentration of iron and manganese: addition of a settling tank, use of sand and anthracite covered with manganese oxides, and aeration. Different oxidants and oxidation sequences were also tested. Results show that the presence of a high quantity of iron significantly improves removal of manganese. These results also confirm that manganese oxidation can be realized with free chlorine inside a filter bed other than greensand, provided that the excess of free chlorine is sufficient. Within the conditions studied, the target area for filtration performances can be attained for every treatment sequence tested and for a filtering aid dose ranging from 0.25 to 0.5 mg/L. Although groundwater aeration leads to better settling performances, it also accelerates head loss in the filtering bed when a filtering aid is present.Key words: groundwater, iron, manganese, pilot study, treatment, separation.
Use of fibre reinforced polymer reinforcement integrated with fibre optic sensors for concrete bridge deck slab construction
Authors: Benmokrane Brahim , Rahman Habib , Mukhopadhyaya Phalguni , Masmoudi Radhouane , Chekired Mohammed , Nicole Jean-François , El-Safty Adel
Published: April 2011

The use of corrosion free fibre reinforced polymer (FRP) composites as reinforcement to concrete is currently being seen as a promising option to generate durable concrete structures. However, there exists very little credible information about its field application and performance. This paper describes the Joffre Bridge project, in Sherbrooke (Québec, Canada), over the St-François River, where Carbon Fibre Reinforced Polymer (CFRP) was used as reinforcement for a portion of the concrete deck slab. The bridge consists of five longitudinal spans with lengths varying from 26 to 37 m. Each span has a concrete deck supported by five steel girders at 3.7 m. A part of the concrete deck slab (7.3 × 11.5 m) and a portion of the traffic barrier and the sidewalk were reinforced with Carbon (CFRP) and Glass Fibre Reinforced Polymer (GFRP) reinforcement. The bridge was extensively instrumented with many different types of gauges, including integrated fibre optic sensors (FOS) into FRP reinforcement. The performance of the bridge had been assessed under static and dynamic loading using calibrated heavy trucks. Moreover, structural design and construction details of the bridge and instrumentation were performed. The results from calibrated field tests on the bridge are presented in this paper.Key words: concrete bridge deck, FRP reinforcement, fibre optic sensors (FOS), field calibrated tests, performance monitoring.
Behaviour of reinforced concrete beams strengthened with carbon fibre reinforced polymer laminates subjected to corrosion damage
Authors: Soudki Khaled A , Sherwood Ted G
Published: April 2011

The viability of carbon fibre reinforced polymer (CFRP) laminates for the strengthening of corrosion damaged reinforced concrete bridge girders is addressed in this paper. Ten reinforced concrete beams (100 × 150 × 1200 mm) with variable chloride levels (0-3%) were constructed. Six beams were strengthened by externally epoxy bonding CFRP laminates to the concrete surface. The tensile reinforcements of three unstrengthened and four strengthened specimens were subjected to accelerated corrosion by means of impressed current to 5, 10, and 15% mass loss. Strain gauges were placed on the CFRP laminates to monitor and quantify tensile strains induced by the corrosion process. Following the corrosion phase, the specimens were tested in flexure in a four-point bending regime. Test results revealed that CFRP laminates successfully confined the corrosion cracking, and the total expansion of the laminate exhibited an exponential increase throughout the corrosion process. All the strengthened beams exhibited increased stiffness over the unstrengthened specimens and marked increases in the yield and ultimate strength. The CFRP strengthening scheme was able to restore the capacity of corrosion damaged concrete beams up to 15% mass loss.Key words: CFRP laminates, corrosion, confinement, expansion, load tests, strengthening, bond strength, reinforced concrete.
A computer model for predicting infilled frame behaviour
Authors: Dawe J L , Seah C K , Liu Y
Published: April 2011

A computer model is developed for the structural analysis of masonry infilled frames. Structural interaction of the panel and its peripheral frame is considered. Various failure criteria are incorporated into the model and special elements are developed to account for masonry failure by cracking and crushing as well as to account for the complex interaction of frame and panel. Comparison of analytical findings with the results of 31 laboratory tests on steel and reinforced concrete infilled frames showed favourable correlation and verification of the computer model.Key words: masonry, infill, frame, steel, concrete, computer, model, testing, correlation, failure.
Biological nitrification and denitrification of a simulated high ammonia landfill leachate using 4-stage Bardenpho systems: system startup and acclimation
Authors: Ilies P , Mavinic D S
Published: April 2011

This research investigated the nitrogen removal capability of two biological nitrification systems, with pre- and post-denitrification, when treating a landfill leachate characterized by high ammonia concentrations and low levels of biodegradable organics. The recycle ratios of the systems were set so that, at an average influent flow of 10 L/d, the actual hydraulic retention time of the first anoxic reactor was about 1.5 h for one system and 1.7 h for the other system. The systems also operated at a first aerobic reactor actual hydraulic retention time of 3 and 3.4 h, respectively. Methanol was used as a supplementary organic carbon source for denitrification. High leachate ammonia concentrations were simulated by artificially increasing influent ammonia to about 2200 mg N/L. This paper presents an overview of initial startup and acclimation, as well as some of the direct and indirect effects of methanol addition on process performance. The reported data were collected during two runs at incrementally increasing influent ammonia concentrations. During the first run to reach 2200 mg N/L, methanol loading rates were increased concomitantly with ammonia loading rates, to match expected aerobic NOx production, using a CH3OH:NOx of about 20:1. This resulted in methanol carry-over into the first aerobic zone, enhanced aerobic heterotrophic growth, and further inhibition of the nitrifying population, already inhibited by recycling through the elevated "free" ammonia levels of the first anoxic zone. When these systems were allowed to adapt up to 14 days, rather than 7 days, initially, to each incremental ammonia increase, and with methanol loading rates subsequently changed to yield CH3OH:NOx of only 5:1, the influent ammonia concentration was increased to approximately 2200 mg N/L within 88 days from the start of the second run, without any inhibitory problems. The timing and levels of ammonia and methanol loading rate increases, with respect to each other and to the corresponding previous loading rate increase, played an important role in system stability and the onset of nitrification failure.Key words: biological treatment, high ammonia leachate treatment, denitrification, methanol, nitrification.
Integration of heuristic knowledge with analytical tools for the selection of flood damage reduction measures
Authors: Ahmad Sajjad , Simonovic Slobodan P
Published: April 2011

Heuristic knowledge has been integrated with analytical tools to support decision making for flood management. Development of an expert system called Intelligent Flood Management System for the selection of appropriate flood damage reduction measures for a given area is described. The selection of flood damage reduction measures is based on hydraulic, hydrological, geotechnical, environmental, and economic factors related to the river system and the area to be protected from floods. The knowledge base of the Intelligent Flood Management System is generic and can be used to identify a suitable flood management option for any area. The model base of the Intelligent Flood Management System consists of the hydraulic analysis package HEC-RAS, the flood damage analysis program HEC-FDA, and a model for economic analysis. The graphical user interface is developed for effective communication with the system. The developed system has been implemented to identify appropriate flood damage reduction options for the town of Ste. Agathe in Manitoba, Canada using data from 1997 flood in the Red River Basin.Key words: flood control, flood management, structural measures, heuristic knowledge, decision support systems, expert systems.
Hydraulic turbine efficiency
Authors: Gordon J L
Published: April 2011

A set of empirical equations has been developed which defines the peak efficiency and shape of the efficiency curve for hydraulic turbines as a function of the commissioning date for the unit, rated head, rated flow, runner speed, and runner throat or impulse turbine jet diameter. The equations are based on an analysis of peak efficiency data from 56 Francis, 33 axial-flow, and eight impulse runners dating from 1908 to the present, with runner diameters ranging from just under 0.6 m to almost 9.5 m. The metric specific speeds (nq) ranged from 5.3 to 294. The root mean square error of the calculated peak efficiency for Francis and axial-flow runners was found to be 0.65%. The shape of the efficiency curves was derived from eight Francis, five Kaplan, three propeller, and four impulse turbines. Charts showing the relationship between calculated and actual efficiency curves for these 20 runners are provided. A good match between calculated and measured or guaranteed efficiency was obtained. The equations were also used to determine the relative increase in peak efficiency for new reaction runners installed in existing casings at 22 powerplants, with a root mean square accuracy of 1.0%. The equations can be used to (i) develop efficiency curves for new and old runners; (ii) compare the energy output of alternative types of turbines, where this choice is available; and (iii) calculate the approximate incremental energy benefit from installing a new runner in an existing reaction turbine casing, or onto the shaft of an impulse unit.Key words: hydraulic turbines, turbine renovation, turbine efficiency.
Review of shear design methods for reinforced concrete beams strengthened with fibre reinforced polymer sheets
Authors: Deniaud Christophe , Cheng JJ Roger
Published: April 2011

This paper reviews the different shear design methods found in the literature for reinforced concrete beams strengthened externally with fibre reinforced polymer (FRP) sheets and compares the adequacy of each method by using the test results from the University of Alberta. The FRP shear design methods presented include the effective FRP strain and the bond mechanism criteria, the strut-and-tie model, the modified compression field theory, and a mechanical model based on the strip method with shear friction approach. Sixteen full-scale T-beam test results were used in the evaluation. Two web heights of 250 and 450 mm and two ready mix concrete batches of 29 and 44 MPa were used in the test specimens. Closed stirrups were used with three spacings: 200 mm, 400 mm, and no stirrups. Three types of FRP were used to strengthen externally the web of the T-beams: (i) uniaxial glass fibre, (ii) triaxial (0/60/60) glass fibre, and (iii) uniaxial carbon fibre. The results showed that the mechanical model using the strip method with shear friction approach evaluates better the FRP shear contribution. The predicted capacities from this mechanical model are also found conservative and in excellent agreement with the test results.Key words: beams, carbon fibres, composite materials, fibre reinforced polymers, glass fibres, rehabilitation, reinforced concrete, shear strength, sheets, tests.
Contamination of a calcareous soil by battery industry wastes. I. Characterization
Authors: Wasay S A , Parker W J , Van Geel P J
Published: April 2011

A study of soil contamination due to the disposal of waste from a battery industry was conducted. The soil particle size, organic matter content, and buffering capacity were characterized. The heavy metal content of the soil was characterized with soil depth, soil particle size, and with respect to the fraction of the soil by which it was retained. Lead was found to be the dominant contaminant with all other metals present at considerably lower concentrations. Most of the lead was retained in the fraction of the soil that had a particle size less than 2 mm. This fraction represented 40.8% of the soil and contained 24 600 mg Pb/kg of soil. A particle size analysis indicated that 45.3% of soil particles were found to be greater than 4.75 mm. The pH of the contaminated soil in water was found to be 7.6 and was similar to the background soil. The similarity in pH was attributed to the high calcium content of the native soil. The lead content in the native soil that was collected 100 m away from the contaminated site was found to be 1967 mg/kg in the soil with particle sizes less than 2 mm (contaminated soil). The difference in pH between KCl solution (pH 7.0) and in water was found to be 0.6 indicating that the pH value was above the point of zero salt effect. An evaluation of the buffering capacity revealed that 297 mL of 0.5 M HNO3 per kg of soil was required to substantially modify the soil pH. The heavy metals in the soil were sequentially extracted to quantify the water soluble, exchangeable, carbonate, oxides, organic matter, and residual fractions. The Pb concentrations were mainly found in the carbonate and oxide fractions of the soil.Key words: heavy metals, soil pollution, characterization, retention form.
Probabilistic assessment of pavement conditions
Authors: Hong H P , Somo S
Published: April 2011

Pavements are subjected to repeated traffic and environmental actions. These actions lead to the degradation of pavement and affect the pavement performance. The assessment of pavement performance is important not only for selecting pavement design parameters but also for choosing pavement maintenance and rehabilitation strategies. The traffic loads, the environmental actions, and the properties of pavement material are uncertain. These uncertainties must be taken into account when predicting the pavement performance. Since the traffic and environmental actions vary with time, they should be modeled as stochastic processes. In this study, stochastic models of the net traffic load growth and environmental actions are proposed based on the rectangular pulse processes. These models can be used in conjunction with the Ontario Pavement Analysis of Cost (OPAC) model to predict flexible pavement performance in a probabilistic framework. The prediction of pavement performance for a typical pavement was carried out by using the simple simulation technique and the first-order reliability method. The analysis results suggest that the predicted pavement serviceability measured in terms of the riding comfort index depends on the correlation between traffic effects in each year and the correlation between the environmental actions in each year. The results also suggest that the uncertainty in the riding comfort index is controlled by the uncertainty in traffic and environmental actions in the early stage of service, while it is dominated by the material property of the subgrade in the later stage of service.Key words: deterioration, reliability, pavement, serviceability, stochastic process.
Evaluation of design requirements for footbridges excited by vertical forces from walking
Authors: Pimentel R L , Pavic A , Waldron P
Published: April 2011

The continuing trend towards the design of more slender, lighter, and livelier footbridges has created new challenges that are not properly addressed in a number of widely used codes of practice in Europe and Canada. Recent research into vibration serviceability of slender structures under human-induced dynamic loading suggests that improvements to the existing footbridge design guidelines are possible in the area of modelling human-induced excitation in the vertical direction. This paper evaluates the performance of currently used codes of practice regarding vibration serviceability of footbridges under human-induced loads due to walking. The evaluation is supported by experimental evidence from tests carried out by the authors on potentially lively footbridges. A description of recent research advances is included, together with a comparative analysis of the approaches of some pertinent guidelines used internationally to tackle this design problem. In addition, suggestions are made for re-addressing the problem of vibration serviceability of footbridges by focusing attention on a more realistic definition of vertical pedestrian loading and the corresponding frequency ranges of interest. It was found that the codes are either conservative or lack appropriate safety margins, depending on the frequency range excited by moving pedestrians. This is principally due to the lack of proper consideration for the frequency content of the pedestrian load, which would take into account developments since the 1970s when the scientific data used in the majority of the current codes of practice were produced.Key words: vibration, serviceability, walking, footbridges, design, codes, dynamic loading factor, evaluation.
Comparaison de deux modèles pour la prévision journalière en temps réel des apports naturels
Authors: Ribeiro J , Lauzon N , Rousselle J , Trung H T , Salas J D
Published: April 2011

This study presents a comparison of the performances of two models used for real-time forecasting of daily inflows to the Chute-du-Diable and the Lac-Saint-Jean reservoirs, and the daily flows measured on the Mistassibi River basin. The three drainage basins are located in the Saguenay-Lac-Saint-Jean water system. The first model, a conceptual one, is a global deterministic model that is currently being used by Alcan (Aluminum Company of Canada) to predict daily flows in real time. The second model, which forms the primary focus of this study, is based on the structure of models commonly known as "black-box" models, a generalized formulation of the autoregressive moving average models with exogeneous variable of Box and Jenkins (ARMAX). The Kalman filter is coupled with this model to enable day-to-day adjustment of estimated parameters. Autocorrelation and cross-correlation analyses on the data have made it possible to establish the preliminary structure of the black-box model, that is, one per basin. The final structure was chosen following a sensitivity analysis on the parameters. The models retained are all ARMAX models, the statistical behavior of the residuals having demonstrated their adequacy. Comparison of these ARMAX models with Kalman filter and the deterministic model have led to the following conclusion: the ARMAX models with the Kalman filter are superior to the deterministic model for daily prediction in real time within a horizon of 2 days. For a 3-day horizon, the models are, for practical purposes, equivalent. For a horizon of 4 days or more, the deterministic model is superior to the ARMAX models with Kalman filter.Key words: forecasting, black-box models, Kalman filter, deterministic model, natural inflows.
A framework for applying simulation in construction
Authors: AbouRizk Simaan M , Hajjar Dany
Published: April 2011

Researchers have successfully implemented system simulation concepts for the design and analysis of construction operations over the past two decades. A number of simulation environments have been created mostly following the CYCLONE methodology introduced by Halpin. The successes, however, remain limited to the academic and research environments. Construction companies have yet to demonstrate acceptance of simulation for everyday decision making. In this paper, an approach is presented that will facilitate adoption of simulation by industry. It summarizes five years of close work with a number of construction firms in developing and implementing simulation-based tools at their organizations. The paper also provides an overview of three simulation implementations for an earth moving contractor, an aggregate producer, and a general contractor. The three implementations represent different "world views" of simulation, namely (i) dynamic process interaction, (ii) continuous time-dependent, and (iii) static simulation. The successful implementation of these simulation tools was based on a common visual-object-oriented modeling environment. The successes, failures, and challenges of these implementations are also discussed.Key words: computer modeling, computer simulation, special purpose simulation.
Analyse régionale des crues journalières de la province de Québec
Authors: Anctil François , Martel Nicolas , Hoang Van Diem
Published: April 2011

The regional analysis of floods is a valuable tool in design and management of hydraulic structures such as dams, dikes, and spillways, especially for ungauged sites. Three homogeneous regions have been established through the use of a discordancy test and a homogeneity test on a total of 136 natural or quasi-natural rivers within the territory of the province of Quebec. It is then shown that the generalized standardized regional distribution of extreme values, adjusted by the L-moments, adequately describes the daily floods within each of the three regions. The quality of the adjustment of the regional distributions has successfully been verified through an extensive test applied to each site. Procedures for the use of the results of the regional analysis are also suggested.Key words: flood, regional analysis, homogeneity, province of Quebec.
Oxygen uptake at Parshall flumes
Authors: Zytner Richard G , Rahmé Ziyad G , Labocha Michael
Published: April 2011

Parshall flumes are frequently used to measure flow at municipal wastewater treatment plants. With the flume causing turbulent flow, there is the potential for the emission of volatile organic compounds. To assess the extent of the emissions, laboratory and field measurements at Parshall flumes were completed, using oxygen as a surrogate. The laboratory measurements showed that the most important parameters influencing oxygen uptake were total energy loss and downstream water depth. Satisfactory results were also obtained using drop height. Field results from three municipal wastewater treatment plants showed that oxygen uptake correlated strongly with drop height and only slightly with discharge rate. This is beneficial as downstream water depth is difficult to measure in the field. Findings suggest that the use of an appropriate weir model would allow the estimation of oxygen uptake and volatile organic compounds stripping at Parshall flumes.Key words: oxygen uptake, volatile organic compounds, flumes, wastewater.
Project management information control systems
Authors: Shahid Syed , Froese Thomas
Published: April 2011

Construction managers rely on ready access to a large amount of project information. The entry, processing, and flow of information are important in avoiding problems, delays, and claims on construction projects. This paper describes a study of the extent and nature of project documentation and project information flows within the construction industry. The study mapped various types of project information against the documents that typically provide the information and the construction management functions that provide and access the information. From this analysis, a computer system to support the task of project information management was designed. The problem analysis, requirements specification, system design, and system implementation are described. The system allows construction managers to enter information for a wide variety of project events, cross-reference the various bodies of information, and use the information to monitor and control various aspects of a construction project. The objective of the study was not necessarily to improve upon commercially available project information and documentation tools, but to deepen and formalize our understanding of project information as an input to a larger body of work on integrated project information systems and data standards for the construction industry.Key words: construction management, project management, document control, information flow, databases.
From pristine to present state: hydrology evolution of Lake Saint-François, St. Lawrence River
Authors: Morin Jean , Leclerc Michel
Published: April 2011

Lake Saint-François is a relatively shallow fluvial lake of the St. Lawrence River with numerous deep channels. This complex system has been considerably altered from its pristine state 150 years ago. Currently, the water level is stabilized and the flow is regulated; important areas have been dredged and the major part of its outflow is diverted through the Beauharnois canal. The evolution of water levels shows a trend towards stabilization as required for ship traffic in the St. Lawrence Seaway and for hydropower production. With the construction of the Moses-Saunders dam in 1960, the flow of the river could be regulated; changes occur in the seasonal pattern of the flow. Ancient stage-discharge relationships were recreated to describe the impact of the 1849 damming and of the present level stabilization. Stabilization of the water level has favored the growth of submerged plants. Manning's friction coefficient was used to show that plant biomass has doubled since 1920; the onset of biomass increases corresponds to a water level stabilization event. The distribution of wetlands in the Lake Saint-François area was drastically modified by the water level rise caused by the 1849 damming. New wetlands were created and pre-1849 wetlands, located on what are currently shoals in the central part of the lake, have totally disappeared.Key words: Lake Saint-François, St. Lawrence River, impact of civil works, flow discharge regulation, water level regulation, wetland flooding cycle, submerged macrophyte, ecosystem reaction, civil work history.
Development of design spectra for long-duration ground motions from Cascadia subduction earthquakes
Authors: Tremblay R
Published: April 2011

There is now growing evidence that large-magnitude earthquakes have occurred and could occur again along the Cascadia subduction zone located west of Vancouver Island, Bristish Columbia. Numerical simulations indicate that these earthquakes would produce long-duration ground motions and would thus be capable of inducing a large number of reversals of inelastic deformations in engineered structures. Efforts have now been undertaken to account for this damage potential in building codes. In this paper, inelastic design spectra are developed for Cascadia subduction earthquakes for four sites in British Columbia. These spectra are compared with elastic design spectra that have been developed recently for the same sites based on empirical attenuation relationships for Cascadia events. The approach used to develop the inelastic spectra aims at providing the same level of protection against structural failure for both subduction events and crustal or subcrustal earthquakes. Force modification factors are first determined for structures exhibiting various failure modes and ductility levels when subjected to representative crustal and subcrustal earthquake ground motions. Thereafter, design spectra are developed for the same structures to prevent structural collapse under simulated Cascadia subduction ground motions. The study reveals that the elastic spectra do not reflect adequately the damage potential of Cascadia earthquakes. These elastic spectra generally are unconservative for Tofino and Victoria. For Vancouver and Prince George, the elastic spectra overestimate the demand, especially for short-period structures.Key words: collapse, crustal earthquakes, damage index, design spectrum, ductility, duration, ground motion, subduction zone.
Automated schedule generation
Authors: Chevallier Nicola , Russell Alan D
Published: April 2011

Even for the most well-intentioned companies, the commitment required for the initial drafting of a plan is a real barrier to developing a useful schedule for a construction project. This paper explores how artificial intelligence and expert systems have and can be used for automating the generation of plans and schedules. Findings from a thorough literature review and observations about the general characteristics of projects provide a backdrop to explain the reasoning that has led to the authors' approach to developing a module capable of generating draft plans and schedules. This approach combines expert systems with large building blocks of predefined project scoping, sequencing, and scaling knowledge contained in standard templates and rules. It relies on templates to store much of the reasoning needed to produce a project plan and schedule, and on the use of generalized planning structures as activities. A draft schedule can then be automatically generated by way of a relatively simple rule set that assigns activity property values dealing with physical locations and production rates, as well as other project scale related values. The role of a physical model or view of a project is emphasised.Key words: construction, scheduling, project management, expert system, template, automated schedule generation, rule based, computer integration.
Modeling of wind-induced pressure fluctuations on roofs of low-rise buildings
Authors: Kumar K Suresh
Published: April 2011

A systematic study on the modeling of wind-induced pressures on low building roofs with application to extreme value and fatigue analysis is described in this paper. Extensive wind tunnel measurements form a basis to carry out the modeling. Based on the Fourier representation of time series, a general approach for simulating Gaussian as well as non-Gaussian wind pressure fluctuations has been presented. Both Fourier amplitude and phase required for the simulations are modeled individually. A simple stochastic model is proposed for the generation of Fourier phase of non-Gaussian time series. An empirical model has been suggested for the synthetic generation of normalized spectra; synthetic spectra are utilized for the generation of Fourier amplitude part. Towards the generalization of the simulation scheme, the standard spectral shapes associated with various zones of each roof and their parameters are established. The efficiency of this simulation methodology is illustrated with several examples. Applications of the simulation methodology have also been discussed. The established simulation scheme can be used to generate fluctuating wind pressures on low building roofs in a generic fashion not only for the evaluation of extreme pressures but also for fatigue design purposes.Key words: low-rise building, modeling, roofs, wind pressure.
Background to the general method of shear design in the 1994 CSA-A23.3 standard
Authors: Rahal Khaldoun N , Collins Michael P
Published: April 2011

The 1994 CSA-A23.3 standard "Design of concrete structures" includes a new shear design method based on the equations of the modified compression field theory (MCFT). This "general method" is a simplification which casts the MCFT in the traditional "Vc + Vs" format resulting in a set of six general equations and two tables. This new method unifies the treatment of reinforced, partially prestressed and fully prestressed concrete and accounts, in a rational manner, for the effects of axial load and bending moment on shear capacity. Simplifying the MCFT while maintaining acceptable generality and accuracy involved a number of considerations and assumptions. This paper gives the background to the development of these shear design equations and tables of the general method.Key words: beams, building codes, crack width and spacing, diagonal cracking, reinforced concrete, shear strength, size effect in shear, structural design.
Alkali-aggregate reactions in Ontario
Authors: Rogers Chris , Grattan-Bellew P E , Hooton R Doug , Ryell J , Thomas M DA
Published: April 2011

In Ontario, two types of alkali-aggregate reaction exist. Each type is evaluated using different tests. Over the past few years, new tests have been introduced to replace some existing test methods. The new tests are faster and more reliable. Preventive measures such as the use of low-alkali cement and supplementary cementing materials, while they are effective, have not been extensively used with reactive aggregate in Ontario. Beneficiation or selective extraction is used with some potentially reactive aggregates.Key words: alkali-aggregate reaction, concrete, cracking, Ontario, structures.