The Evolution of Municipal Asset Management Maturity in Canada: Surveying Mid-Sized Cities and Evaluating Federal and Provincial Policies to Spur Municipal Asset Management Practice

In today’s global economy, Canada’s cities play a key role in the country’s economic growth and prosperity. They must build and maintain significant amounts of public infrastructure. However, the large and ever-growing national infrastructure deficit threatens to undermine the country’s competitiveness and quality of life. Since the turn of the century, the federal and provincial governments have increased reinvestment in infrastructure and employed several policy approaches to spur municipalities towards formalized asset management (AM) practice, which is widely recognized as the optimal means for determining long-term maintenance and funding requirements. Given the varied policy approaches, the state of municipal AM maturity might also be expected to differ across the country. Large municipalities have generally progressed much further than small municipalities, whose resources are very limited. Less is known about mid-sized cities, however, where perhaps more variation can be expected. Therefore, this paper surveys the current AM maturity of mid-sized Canadian cities using the Federation of Canadian Municipalities AM Readiness Scale, finding that most respondents are in the early stages of AM practice, though BC and Ontario seem to be further ahead of other provinces. The paper also assesses the effectiveness of the federal and provincial policies, classifying them using Christopher Hood’s NATO framework and finding that, while they produced some incremental progress towards AM practice, success was limited because they did not address the key challenges municipalities faced, such as the lack of internal capacity to develop AM practice. The paper concludes with a few observations and considerations for future policy-making in Canada’s multi-level governance context

Experimental study on the effect of pressure on single and two stage combustion of decomposed ammonia (NH3-H2-N2) blends over a swirl stabilized burner

Ammonia (NH3) is a practical hydrogen vector for gas turbine power generation, but struggles to be deployed commercially due to many unresolved technical and fundamental challenges. This experimental investigation focuses on combustion of fuel blends representatives of various NH3 decomposition (or cracking) ratios in a combustor fitted with a swirl-stabilized burner, exploring pressures ranging from atmospheric to 10 bar. The study presents measurements of flame stability and emissions of NOx and N2O in combustor strategies relevant to both conventional single lean operation and staged with a rich primary zone, as a function of decomposition ratios (DR) and primary zone equivalence ratio. The findings reveal a notable pressure-dependency of nitrogen oxides (NOx) during combustion of ammonia containing fuels. For a fully decomposed mixture (H2 single bondN2 at 75/25 %vol.), NOx emissions increase with increasing pressure. Conversely, when ammonia is present in the fuel, the trend reverses. However, the majority of NOx reduction occurs within a limited range of pressure increase and reaches a plateau thereafter. The transition at which the pressure effect declines depends on other factors, and was seen to occur between 5 and 9bar in the conditions of this study. Notably, NOx levels in flames containing NH3 are significantly higher, rendering the pressure sensitivity on NOx primarily governed by NH3 presence, irrespective of its concentration in the fuel (i.e. DR). Furthermore, the study reveals a non-monotonic relationship between NOx emissions and NH3 concentration in the fuel, peaking at mid-decomposition ratios. All factors tending to weaken flame stability (e.g. increasing fuel NH3 content, approaching lean/rich blow off limits, or increasing burner exit velocity) favour emissions of N2O emissions. As a general trend, it appears that longer residence times, increased pressure, and rich primary zone operation are all parameters limiting NOx formation from all partially decomposed blends of ammonia, but that they only positively add to a certain limit of a few hundred ppm. This NOx plateau level being higher at higher NH3 content in the fuel. Finally, the fuel obtained by perfectly decomposing ammonia appears to be the optimal fuel associating strong flame stability and low NOx propensity, even for the non fully premixed burner type of this study.publishedVersio

Experimental study on high pressure combustion of decomposed ammonia: How can ammonia be best used in a gas turbine?

Hydrogen, a carbon-free fuel, is a challenging gas to transport and store, but that can be solved by producing ammonia, a worldwide commonly distributed chemical. Ideally, ammonia should be used directly on site as a fuel, but it has many combustion shortcomings, with a very low reactivity and a high propensity to generate NOx. Alternatively, ammonia could be decomposed back to a mixture of hydrogen and nitrogen which has better combustion properties, but at the expense of an endothermal reaction. Between these two options, a trade off could be a partial decomposition where the end use fuel is a mixture of ammonia, hydrogen, and nitrogen. We present an experimental study aiming at finding optimal NH3-H2-N2 fuel blends to be used in gas turbines and provide manufacturers with guidelines for their use in retrofit and new combustion applications. The industrial burner considered in this study is a small-scale Siemens burner used in the SGT-750 gas turbine, tested in the SINTEF high pressure combustion facility. The overall behaviour of the burner in terms of stability and emissions is characterized as a function of fuel mixtures corresponding to partial and full decomposition of ammonia. It is found that when ammonia is present in the fuel, the NOx emissions although high can be limited if the primary flame zone is operated fuel rich. Increasing pressure has shown to have a strong and favourable effect on NOx formation. When ammonia is fully decomposed to 75% H2 and 25% N2, the opposite behaviour is observed. In conclusion, either low rate or full decomposition are found to be the better options. Copyright © 2021 by ASME.publishedVersio

Emission characteristics of a novel low NOx burner fueled by hydrogen-rich mixtures with methane

The use of hydrogen-rich fuels may be challenging for burner designers due to unique properties of hydrogen compared to conventional fuels such as natural gas. Burner retrofit may be required to use hydrogen-enriched fuels in combustion systems that are designed for natural gas combustion. This study aimed to experimentally investigate NOx emissions from a novel low NOx burner fueled by methane-hydrogen mixtures. The burner was tested in a cylindrical combustion chamber at atmospheric pressure. Burner thermal load of 25 kW (LHV) and air-fuel equivalence ratio of 1.15 were maintained throughout the experimental campaign. The influence of burner design parameters on NOx emissions was tested for various fuel compositions using a statistically cognizant experimental design. The study revealed that shifting the burner head upstream can deliver NOx emission reduction. In contrast, supplying fuel to the burner through secondary fuel ports increases NOx emissions, particularly when the burner head is shifted upstream. The lowest predicted NOx emissions from the burner are below 9 ppmvd at 3% of O2 and 14 ppmvd at 3% of O2 for 5% and 30% mass fraction of hydrogen in the fuel, respectively.Open Access article

Calculation of flight vibration levels of the AH-1G helicopter and correlation with existing flight vibration measurements

Boeing Helicopters, together with other U.S. Helicopter manufacturers, participated in a finite element applications program to give the United States a superior capability to utilize finite element analysis models in support of helicopter airframe design. The program was sponsored by the NASA Langley Research Center. Under this program, an activity was sponsored to evaluate existing analysis methods applicable to calculate coupled rotor-airframe vibrations. The helicopter used in this evaluation was the AH-1G helicopter. The results of the Boeing Helicopters efforts are summarized. The planned analytical procedure is reviewed. Changes to the planned procedure are discussed, and results of the correlation study are presented

Predicting radiative heat transfer in oxy-methane flame simulations: An examination of its sensitivities to chemistry and radiative property models

publishedVersio

Application of reverse micelle sol-gel synthesis for bulk doping and heteroatoms Surface Enrichment in Mo-Doped TiO 2 nanoparticles

TiO 2 nanoparticles containing 0.0, 1.0, 5.0, and 10.0 wt.% Mo were prepared by a reverse micelle template assisted sol-gel method allowing the dispersion of Mo atoms in the TiO 2 matrix. Their textural and surface properties were characterized by means of X-ray powder diffraction, micro-Raman spectroscopy, N 2 adsorption/desorption isotherms at -196 °C, energy dispersive X-ray analysis coupled to field emission scanning electron microscopy, X-ray photoelectron spectroscopy, diffuse reflectance UV-Vis spectroscopy, and ζ-potential measurement. The photocatalytic degradation of Rhodamine B (under visible light and low irradiance) in water was used as a test reaction as well. The ensemble of the obtained experimental results was analyzed in order to discover the actual state of Mo in the final materials, showing the occurrence of both bulk doping and Mo surface species, with progressive segregation of MoO x species occurring only at a higher Mo content

High resolution satellite ortho-images for archaeological research: different methods and experiences in the Near and Middle East

The paper concerns the very significant contribution of satellite ortho-images to archaeological research. The unavailability of cartography, updated or in adequate scale, is a recurring problem for archaeological research operating in urban and territorial contexts, and in the last years interesting experiences have been carried out with the use of satellite ortho-images; they can provide constant support to field work, both excavations and surveys, and to the management of data in archaeological GIS. As an example of this, the paper shows the results achieved by three research projects carried out by CNR-IBAM in the Near and Middle East, the Hierapolis of Phrygia Survey Project, the Tell Tuqan Survey Project and the Iraq Virtual Museum Project in which base-maps and cartographies satellite ortho-images have been widely used. In these projects, the use of very high resolution satellite images was necessary because large scale and updated cartographies and aerial photos are not available. In the examples shown, satellite ortho-images have different uses, often linked to the possibility or not of an accurate ortho-rectification, with the possibility of the collection of Ground Control Points and with the availability of high resolution DEMs. These images were used to create space-maps for the field work, as well as to realize and update archaeological maps and cartographies finalized to archaeological research. In the cases study presented, WorldView-1, QuickBird-2 and Ikonos-2 images, also stereo-pairs, were used