Search

A tracking control scheme is proposed for complex dynamic network (CDN), where the CDN is regarded wholly as a dynamic composite system which consists of two mutually coupled subsystems. One subsystem consists of all nodes and the other consists of all links, and consider the weights of the links to be state variables in the latter subsystem. There are two parts in the structure of the proposed tracking control scheme: the designed controller of nodes and the synthesis of the coupling term in links. These two parts can guarantee two subsystems to asymptotically track the given reference targets, respectively. This approach originates from the communication transmission network (CTN). In CTN, for the network optimization management, the reference network topology (NT), such as the star topology, is required as a target for tracking in communication transmission (links) when each node in network needs to track its own target. The control scheme provided of this paper coincides with above requirement. And finally, a comparative simulation example is given for illustrating the effectiveness of the provided control scheme. • The dynamic equations of nodes and NT are represented by the matrix differential equations, this can contain many models in other papers and simplify the control scheme, which is rarely discussed. • The tracking targets of nodes and NT given in this paper are independent of each other, which is novel. • When all nodes track the reference targets, the eventual network layout is shown by the desired NT, which is novel. [ABSTRACT FROM AUTHOR]

The performance of constant false alarm rate (CFAR) detectors is often severely degraded in clutter edge and under multiple target interference. CFAR detection in the above environments often uses generalised likelihood ratio method or mean ratio method to find out the clutter edge demarcation line and suppress the sharp increase of false alarm rate, or remove the interference and modify the threshold factor to suppress the interference and improve the detection performance, but this sacrifices the detection gain from the number of clutter samples. In this paper, the feature information is fused to construct feature vectors, and the edge location is judged by the modulus of the cross product of the feature vector pair (MCPFVP), this edge demarcation line detection method fusing with features can be implemented without the need of clutter statistical distribution information. In addition, this paper reconstructs the sea clutter masked by multiple target interference by fusing the sea clutter amplitude correlation information, and these reconstructed sea clutter samples are used for power estimation together with the unmasked sea clutter without changing the threshold factor. This method can not only suppress the target masking effect of multiple target interference as the censoring type CFAR detector, but also maintain the detection gain from the number of clutter samples, which is not possible with the traditional censoring type CFAR detector. In addition, the relative weighted ratio summation (RWRS) is proposed to detect the multiple target interference, which takes into account the asymmetry of the shape of the statistical distribution. Both simulated and real sea clutter data are used to validate the above methods. The measured data are obtained from radar data collected at Yantai Yangma Island, China, Darmouth, Canada and Grimsby, Canada. (The latter two datasets are collected by the IPIX radar - Ice Multiparameter Imaging X-Band Radar). [ABSTRACT FROM AUTHOR]

The pulp and paper industry use biomass residues, such as paper sludge and bark as fuel to provide energy for their plants. However, issues such as high-water content or low heating value limit the amount of energy that can be utilized. Processes to improve heat generation include biomass densification, which facilitates transportation and handling and can increase energy yield. However, the technical feasibility of briquetting is a function of the feedstock and preprocessing. This study introduces a novel approach to briquette production from biomass residues by utilizing wet biomass with water as a natural binder, contrasting with conventional methods that require forced drying and/or the addition of binders. The objective of this research was to investigate the impact of briquetting both unprocessed biomass and post-hydrothermal carbonization. The study focused on manufacturing briquettes derived from different sources, including bark (Balsam fir), paper sludge, and hydrochar of paper sludge. The feedstock was characterized for ash content and higher heating value. Biomass particle size (range), moisture content (range), process temperature (range), process pressure (range), and process residence time (range) were varied in briquetting experiments to determine conditions to produce high-quality briquettes with minimal energy input. Moisture content as high a 50 wt% in feedstock produced technically feasible briquettes, with appropriate physical-mechanical properties (durability, volumetric expansion and apparent density), and energetic potential (calorific value). The addition of heat (pressing temperature of 150 °C) during the pressing process resulted in briquettes with enhanced physical-mechanical, and energetic properties, surpassing those produced at room temperature. Further tests with additional steps in the production process are required to meet commercialization standards in Canada, but the treatments conducted in this study effectively improved the energy potential of biomass for internal industrial energy gains. • Wet briquettes (20 wt% and 50 wt%) production was technically feasible. • Briquettes with added heat (150 °C) exhibited superior properties. • All biomass briquettes exhibited improved energy potential. • Hydrochar briquettes showed superior energy content and durability. [ABSTRACT FROM AUTHOR]

During the design phase of the Confederation Bridge in Canada, the Canadian government Public Works and Government Services Canada asked the National Research Council (NRC) of Canada to provide information on ice loads from large ridges using a wide range of predictive technologies. The NRC put together a team that looked at loads from several sources including analytical models, physical model tests, finite element models, discrete particle models, and full-scale data. The ice loading scenario was an extreme first-year ridge loading one of the bridge piers. A large number of analytical models were used and the load components were separated into those from the consolidated layer, the sail, and the keel. An upper bound prediction from this approach gave a value of 16 MN on a pier, but the assumptions that were used to arrive at this value did not match observed behavior in the physical and numerical studies of the program. Physical model tests indicated that the loads could be 10.5 MN with a load of 7.3 MN from the keel and 3.2 MN from the consolidated layer and sail. A finite element analysis indicted a range of predicted values of 10 MN to 12 MN depending upon the assumptions used. A discrete particle analysis predicted load values from 2.2 MN to 9.5 MN depending upon the assumptions used in describing the stiffness of the ridge. A review of full-scale measurements on lighthouses and ships suggested that the loads could range from 7.3 MN to 10.4 MN. These predicted values compare to the highest load measured on the Confederation Bridge over a twenty-year span of just over 8 MN. This paper outlines the approaches used for this prediction study and their resulting predictions. It shows the value of using multiple approaches for load predictions for offshore structures in ice-covered waters. • Predictions of ice ridge loads on the Confederation Bridge piers. • Analytical, Physical Modelling and Numerical approaches for ice ridge loading. • Comparison to measured loads on bridge piers. [ABSTRACT FROM AUTHOR]

There are 14 northern communities in Nunavik, the Arctic region of Quebec province, Canada. Transportation infrastructure plays a vital role in the social and economic development of these localities. The thawing of permafrost compromises the stability of northern transportation infrastructure. Harsh Arctic climate conditions limit the installation of effective monitoring systems to assess infrastructure stability. In Akulivik, the access road connects the Akulivik airport and the village of Akulivik. There is no monitoring to observe the thermal condition of the permafrost foundation of the access road, hindering the capacity to perform preventive maintenance activities, especially in the context of observed climate warming in Nunavik. This paper describes a project aiming at the assessment of the stability of the access road using a new approach and proposes adaptation solutions to stabilize the road, based on design tools recently developed. Particular attention was paid to the foundation soil under the side slope where relatively rapid permafrost degradation was occurring due to accumulated snow. The results indicate a positive thermal gradient of 0.29 °C/m under the side slope and a near-zero thermal gradient under the centerline. Projected climate warming was also considered to further investigate the thermal condition, providing a safety margin for the design of promising adaptation solutions. These results assist government agencies in evaluating the thermal conditions of underlying permafrost and deploying potential adaptation solutions in Akulivik. • The thermal conditions of the road embankment were analyzed. • A new approach was employed to assess the thermal stability of the road embankment. • An adaptive solution was designed to mitigate permafrost degradation beneath the embankment side slopes. [ABSTRACT FROM AUTHOR]

Thunderstorm winds are the costliest wind hazard in Canada, but they have not been well studied. This paper investigates atmospheric conditions prone to downbursts in Canada using a combination of reported downbursts from damage survey reports, ERA5 reanalysis data, lightning flash observations, radar imagery, and upper air measurements for the period of 2019–2023. We propose a novel Downburst Precursor Parameter (DPP) by integrating two low-correlated thermodynamic and kinematic parameters. DPP outperforms other existing instability indices in downburst diagnosis in Canada. Our spatial analysis reveals the absence of damaging downbursts west of the Rockies, while approximately half of all recorded damaging downbursts occurred in southeastern Canada. Squall lines and supercells are the most common types of downburst-generating storms in Canada. Furthermore, nearly two-thirds of storms are squall lines when a downburst is accompanied by lightning flashes, which occurred in ∼71% of all cases. The remaining ∼29% of downbursts without lightning are mostly dry downbursts, typically displaying a disorganized pattern of convective storms on a radar screen. The equivalent potential temperature difference between the surface and mid-level in the troposphere (∆ θ e) exceeds 13 K prior to 61% of damaging downbursts. This result indicates that ∆ θ e might be a useful downburst indicator in Canada despite lower values compared to many regions in the United States. [Display omitted] • Convective parameters for diagnosing downburst-prone environments were investigated. • Novel Downburst Precursor Parameter (DPP) enhances downburst diagnosis accuracy. • DPP > 0.7 signals highest risk for downburst development. • Squall lines and supercells are the dominant storm types with a ratio of 2:1. • Surface-to-midlevel equivalent potential temperature difference is a useful downburst index. [ABSTRACT FROM AUTHOR]

Access to safe drinking water remains a significant challenge for many Indigenous communities in Canada, particularly for remote communities. This stems from historic colonial practices of water governance that have relied on Western worldviews and excluded Indigenous Peoples. Using an Indigenist research framework and a Community-Based Participatory Research design, we, as Indigenous and non-Indigenous collaborative research team wanted to learn from remote Indigenous communities, including Star Blanket Cree First Nation and the Cumberland House Village at the Treaty 4 and 5 territories (known as Saskatchewan) that have not been adequately represented in water governance. Following this, we used storytelling and deep listening to engage seven Elders and knowledge-keepers from the two communities. The findings show Indigenous People have spiritual and historical worldviews and practices surrounding water and its governance. Promoting Indigenous worldviews in water governance is critical to enhancing access to safe drinking water within the two communities. Therefore, reviving and reconnecting Indigenous drinking water governance promotes community healing and water protection. Insights from this paper propose a meaningful bridge between Western and Indigenous perspectives and the capacity to govern water through deep and complex practices and meanings of water governance. • Remote Indigenous communities lack access to safe drinking water. • Understanding the spirituality of water is key to Indigenous water governance. • Reclaiming Indigenous water stories is key to water reconciliation. • Collaborative water governance enhances access to safe drinking water. • Collaborative water governance promotes sovereignty and self-governance. [ABSTRACT FROM AUTHOR]

This paper investigates the relationships among the important process parameters that impact Post-combustion Carbon Capture (PCC) carbon dioxide (C O 2) separation. A better understanding of the complex relationships among those parameters can support optimization and performance enhancement of the separation process. Being able to precisely predict the process parameters will enable the operator to determine the current state of the process, forecast any potential changes or events, and adjust process parameters to enhance the plant's performance. With the objective of studying the process parameters' correlations in the amine-based PCC process, we modeled the multi-year historical production data of the Clean Energy Technologies Research Institute (CETRi) (formerly known as the International Test Center for PCC or ITC) in Regina, Saskatchewan, Canada, using a Decision Forest approach. The model validation process revealed that the Decision Forest model produced higher predictive accuracy than previous efforts. The Decision Forest models we developed also represent knowledge about the importance of parameters involved in the capture process, and such knowledge is useful for further optimization of the capture process in the future. • Modeling the parameters of the Carbon Capture process with machine learning (ML). • The ML models used Decision Forest with Gradient Boosting and Oblique Split. • The ML models achieved superior predictive accuracy compared to past efforts. • The ML models support interpretability by visualizing weights and prediction paths. [ABSTRACT FROM AUTHOR]

Geothermal systems installed at intermediate depths (∼1–2 km) in sedimentary basins represent an attractive option to provide low-carbon heat in cold countries, even where the geothermal gradient is low, using either closed- or open loop systems combined with heat pumps. However, the installation of such systems is costly and risky due to the uncertainty associated with the geological, hydrogeological and thermal properties of the targeted unit(s). Additionally, the performance of different types of systems is seldom compared in the literature for a given geological context. This paper presents a numerical approach to readily assess the maximum energy that could be produced by different geothermal systems (a deep borehole heat exchanger (DBHE) and three types of doublets) and compare their performance for preselection purposes. Since deep formations are often poorly characterized, the sensitivity of these systems to the most impactful site properties is evaluated. For each scenario of site properties, the systems were simulated for different operation flow rates. The maximum usable flow rate is determined from simulation results. The flow rate maximizing net energy production is used for the DBHE, while the maximum flow rate ensuring safe injection pressure has been selected for the doublets. The heating power produced per length drilled and system COP are calculated for each simulation and interpolated for the maximum usable flow rate to fairly compare the systems' performance. An illustrative case using the Bécancour area (eastern Canada) highlights that, even if the site stratigraphy and properties have been relatively well characterized previously, uncertainty regarding key properties significantly affects simulation results and, consequently, the choice of the geothermal system to install. Our numerical approach is intended as a decision-making aid in order to properly plan the installation of these expensive systems. [Display omitted] • New method for pre-selecting 1–2 km geothermal systems and assess heating potential. • Compares the DBHE and geothermal doublet performances for various designs. • Includes a sensitivity analysis to permeability, thermal conductivity and heat flux. • Determines the maximum usable flow rate for each system and scenario. • An application demonstrates the need to consider the uncertainty of rock properties. [ABSTRACT FROM AUTHOR]

Valued components (VCs) are at the core of impact assessment (IA), cumulative effects management (CEM), and other environmental planning and management processes. However, the research that exists on VC selection identifies major conceptual and methodological flaws in the conventional approaches used in most project-based IAs, including poor understanding, inadequate guidance, insufficient engagement with local stakeholders and Indigenous communities, and failure to incorporate local and Indigenous perspectives, knowledge, and values in decision-making. To address these flaws, this paper proposes a new community-based method for selecting VCs, which was developed in the Indigenous-led CEM program of the Metlakatla First Nation (located on the northwest coast of Canada). The new VC selection method is grounded in Indigenous values and informed by Indigenous and local knowledge as well as scientific research. It uses a six-step approach to identify VCs and prioritize them, based on clear decision-making criteria, deliberative community dialogue, and explicit consideration of implementation constraints. The Metlakatla First Nation used this method to identify high-priority VCs for their CEM program, but the method could also be adapted for use in project-based IA and other planning and management processes to improve VC selection. A comparison of the results of the application of the new method in the Metlakatla CEM Program with the results of a recent conventional proponent-led IA of a large industrial project in Metlakatla territory shows that the new method addresses many of the deficiencies in the conventional model and generates a substantially different set of high-priority VCs that better reflect Indigenous values and knowledge. • A new community-based method for choosing valued components in impact assessment. • Key features are clear criteria, deliberative dialogue, and implementation planning. • Applied in Metlakatla First Nation's Indigenous-led cumulative effects program. • Metlakatla CEM Program is a proactive system for monitoring and managing key values. • Valued components chosen with the new method reflect Indigenous views and values. [ABSTRACT FROM AUTHOR]

The global call to address climate change and advance sustainable development has created rapid growth in research, investment, and policymaking regarding the renewable energy transition of Indigenous communities. From a rightsholder perspective, Indigenous Peoples' vision of sustainability, autonomy, and sovereignty should guide research on their energy needs. In this paper, we present a multi-method, inductive examination to identify gaps between Indigenous communities' expressed needs and rights, and the questions researchers and policymakers investigate in energy transition research conducted in the context of Indigenous communities located in Canada. We combine a systematic review of the extant literature, a scoping review of the grey literature on off-grid communities by Indigenous and non-Indigenous governments and non-governmental policy bodies, qualitative primary data collected via fieldwork, and an in-depth study of an Indigenous-led renewable energy transition study conducted by Haíɫzaqv Nation's Climate Action Team. We holistically examine these different perspectives and identify emergent themes to recommend ways to bridge the gaps between off-grid renewable energy research and stated Indigenous community priorities. Specifically, we recommend designing equitable research practices, understanding community worldviews, developing holistic research goals, respecting Indigenous data sovereignty, and sharing or co-developing knowledge with communities to align with community priorities closely. • There is a research-practice gap in Indigenous communities' energy transitions. • We used a multi-method inquiry integrating Indigenous and Western approaches. • Renewable energy literature diverges from the Indigenous community vision and goals. • Indigenous research methods can reduce the research-practice gap in high-tech fields. • Community-based approaches can use traditional laws to yield actionable outcomes. [ABSTRACT FROM AUTHOR]

Permylene™ demonstration system (PDS), a membrane-based pilot unit for olefin/paraffin separation, is designed and fabricated by Imtex Membranes Corp. (Imtex). The PDS, equipped with pilot-scale Permylene™ elements, is capable of treating up to 3 kg/h of olefin/paraffin mixture. The PDS unit is installed in Imtex's testing lab in Mississauga, Ontario, Canada. Various plant-collected and lab-blended olefin/paraffin mixtures involving ethylene/ethane (C2), propylene/propane (C3), and butene/butane (C4) have been assessed on the unit. This paper is focused on the application of PDS for C3 separation, and a series of remarkable performances that have been achieved by the Permylene™ membrane and PDS unit. Propylene purity of over 98.5 vol% in the permeate/product stream has been reached over a wide range of propylene recovery rates, which could offer significant flexibility to meet various industrial operation conditions. Furthermore, the PDS unit demonstrates its stability and efficiency with 1200 hrs of continuous C3 permeation. Finally, a case study of recovering 90 % of propylene from 15,000 kg/h of C3 is performed to estimate energy consumption in commercial applications. The energy consumption of the Permylene™ process is calculated and compared with that of the distillation process. The result indicates that the energy consumption in PDS is extremely low, equal to only 8 % of that required in distillation. The study undeniably validates Permylene™'s remarkable capability for C3 separation, highlighting its potential as a viable and energy-efficient alternative to traditional distillation. [Display omitted] • The asymmetric membrane and solution replenishing overcome the instability. • This pilot unit is capable of treating up to 3 kg/h of olefin/paraffin mixture. • Propylene purity of 98.5 vol% is reached over a wide range of recovery rates. • Stable performance is shown in 1200 h of continuous C3 permeation. • The energy consumption in PDS equals 8 % of that required in distillation. [ABSTRACT FROM AUTHOR]

Reliable construction project cost estimation relies on accurate quantity takeoffs (QTOs), traditionally done with error-prone 2-D drawings, but the emergence of Building Information Modeling (BIM) has improved QTO speed, accuracy, and reliability. However, the quality of BIM models can influence quantity accuracy, an aspect often overlooked in research on automating QTO with BIM. This paper develops an integrated framework to automatically extract and visualize construction quantities from BIM models. The system includes a Quantity Precision Check (QPC) module for automating more accurate QTO outputs. These outputs are then automatically transferred to an external database and visualized through a user-friendly dashboard on the Microsoft Power BI platform. This dashboard allows for comparisons between 2-D and BIM quantities and helps track changes in quantities over time due to design changes. The system was successfully validated in an infrastructure construction project in Canada, where it identified a 39% inconsistency in wall elements' material quantities and reduced steel quantity by 10% due to design changes. Overall, the system offers a speedy, reliable, and efficient tool for construction estimators, site managers, and cost control teams to provide accurate quantities to the procurement team and make swift decisions in response to design change impacts on construction costs. • This study introduces an automated QPC/QTO system for architectural and structural BIM models. • A QPC/QTO system workflow was developed to automatically calculate their quantities and check their accuracy in the BIM model. • The Data Extraction and Analysis Module was developed to automatically calculate, and check the accuracy of the quantities of each category. • The Data Visualization Module was developed to visualize the final QTO results and inconsistencies in BIM parameters after each update. • The system can be used as a fast and reliable tool for construction estimators to provide accurate quantities to the procurement team. [ABSTRACT FROM AUTHOR]