Performance Measures of Road Infrastructure - A Life Cycle Thinking Approach

Roads have been an important asset of human society and the approach we adopt towards planning, designing, constructing, operating, and maintaining of the road infrastructure has significant consequences in the long-term for not only the humans, but all species on planet Earth. Hence, the lifecycle performance of the road infrastructure that sustain our socioeconomic development with a low environmental impact, while fulfilling their technical and functional requirements is of critical importance and needs to be improved. This thesis aims to understand the nature of the information that helps improve the performance of road infrastructure over their lifecycle and propose solutions that close the existing research gaps.This thesis is essentially divided into two parts. In the first part, it focuses on the current lifecycle thinking towards the public physical infrastructure. It carries out a survey of the literature to gain a holistic understanding of the current challenges that infrastructure faces, namely population growth, anthropogenic greenhouse gas emissions, land use and coverage change, and abiotic depletion. It then recommends potential approaches to close the identified gaps. The investigation reveals that considering the entire lifecycle of the infrastructure helps avoid partial thinking, which affects the mankind and the ecosystem adversely and results in problem shifting. It shows how the lifecycle-based methods that incorporate uncertainties help enhance the depth of understanding and decisions regarding the lifecycle performance of infrastructure. In addition, it advocates that the collaboration between and within different fields of science and practice needs to be increased to better capture the consequences of various risks and avoid adverse effects.In the second part, a systematic desk (or secondary) research and regular interactions with the Norwegian Public Road Administration (NPRA) were carried out which revealed the following research gaps to improve the environmental and economic performance of the Norwegian road networks: (1) measure environmental performance of the construction machinery over their entire lifecycle based on regionalized data, which helps increase both the resolution and exclusiveness of the results; (2) estimate lifetimes of pavements based on their technical performance, which helps in improving the validity of the results when benchmarking different pavements with respect to different criteria, e.g., environment, economy, and society, and supports the decision-making at different phases of road infrastructure projects; and (3) capture material flows and stocks of road infrastructure, which helps get an overview of the availability in terms of quantities and time of the secondary materials to theoretically substitute the virgin/primary materials. Hence, potential approaches were used by means of different methods and models, namely geographical information systems (GIS), life cycle assessment (LCA), survival analysis, decision tree model, and material flow accounting (MFA), for the three focus areas to bridge the identified gaps. Also, the Norwegian input data were applied to show the proposed approaches quantitatively. Findings from the research carried out in the second part of the thesis show that:\ub7\ua0\ua0\ua0\ua0\ua0\ua0 Although the operation phase of the construction machinery has been studied solely in most of the prior research, the investigation in this research showed that the inclusion of the other phases is equally important. This means that the production, delivery, maintenance, dismantling, waste processing, and circulation of energetic and non-energetic materials at different phases of a machine’s lifespan contribute to the overall environmental impacts. \ub7\ua0\ua0\ua0\ua0\ua0\ua0 The proposed approach to measure the durability of the pavements showed discrepancies between the maintenance records and the technical requirements and explained how different factors increased or decreased the lifetimes of pavements in different traffic classes. In addition, the results from the statistical tables (showing relative values) were transformed to absolute values to ease the readability and comparability of lifetimes between different pavements.\ub7\ua0\ua0\ua0\ua0\ua0\ua0 The amount of stock in the Norwegian road network has continuously increased and in 2017 there were about 420 Mt of road materials in-service. The growth was owing to the continuous expansion of the road networks. However, the growth in the amount of road stock was predicted to increase by 9 % – 10 % between 2018 and 2050 as well, though it was assumed that the network would not expand after 2017

Shapiro like steps reveals molecular nanomagnets' spin dynamics

We present an accurate way to detect spin dynamics of a nutating molecular nanomagnet by inserting it in a tunnel Josephson junction and studying the current voltage (I-V) characteristic. The spin nutation of the molecular nanomagnet is generated by applying two circularly polarized magnetic fields. We demonstrate that modulation of the Josephson current by the nutation of the molecular nanomagnet's spin appears as a stepwise structure like Shapiro steps in the I-V characteristic of the junction. Width and heights of these Shapiro-like steps are determined by two parameters of the spin nutation, frequency and amplitude of the nutation, which are simply tuned by the applied magnetic fields.Comment: 5 pages, 2 figure

Fractional forcing number of graphs

The notion of forcing sets for perfect matchings was introduced by Harary, Klein, and \v{Z}ivkovi\'{c}. The application of this problem in chemistry, as well as its interesting theoretical aspects, made this subject very active. In this work, we introduce the notion of the forcing function of fractional perfect matchings which is continuous analogous to forcing sets defined over the perfect matching polytope of graphs. We show that our defined object is a continuous and concave function extension of the integral forcing set. Then, we use our results about this extension to conclude new bounds and results about the integral case of forcing sets for the family of edge and vertex-transitive graphs and in particular, hypercube graphs

Development of Hybrid Electromagnetic Dampers for Vehicle Suspension Systems

Vehicle suspension systems have been extensively explored in the past decades, contributing to ride comfort, handling and safety improvements. The new generation of powertrain and propulsion systems, as a new trend in modern vehicles, poses significant challenges to suspension system design. Consequently, novel suspension concepts are required, not only to improve the vehicle’s dynamic performance, but also to enhance the fuel economy by utilizing regeneration functions. However, the development of new-generation suspension systems necessitates advanced suspension components, such as springs and dampers. This Ph.D. thesis, on the development of hybrid electromagnetic dampers is an Ontario Centres of Excellence (OCE) collaborative project sponsored by Mechworks Systems Inc. The ultimate goal of this project is to conduct feasibility study of the development of electromagnetic dampers for automotive suspension system applications. With new improvements in power electronics and magnetic materials, electromagnetic dampers are forging the way as a new technology in vibration isolation systems such as vehicle suspension systems. The use of electromagnetic dampers in active vehicle suspension systems has drawn considerable attention in the recent years, attributed to the fact that active suspension systems have superior performance in terms of ride comfort and road-handling performances compared to their passive and semi-active counterparts in automotive applications. As a response to the expanding demand for superior vehicle suspension systems, this thesis describes the design and development of a new electromagnetic damper as a customized linear permanent magnet actuator to be used in active suspension systems. The proposed electromagnetic damper has energy harvesting capability. Unlike commercial passive/semi-active dampers that convert the vibration kinetic energy into heat, the dissipated energy in electromagnetic dampers can be regenerated as useful electrical energy. Electromagnetic dampers are used in active suspension systems, where the damping coefficient is controlled rapidly and reliably through electrical manipulations. Although demonstrating superb performance, active suspensions still have some issues that must be overcome. They have high energy consumption, weight, and cost, and are not fail-safe in case of a power break-down. Since the introduction of the electromagnetic dampers, the challenge was to address these drawbacks. Hybrid electromagnetic dampers, which are proposed in this Ph.D. thesis, are potential solutions to high weight, high cost, and fail-safety issues of an active suspension system. The hybrid electromagnetic damper utilizes the high performance of an active electromagnetic damper with the reliability of passive dampers in a single package, offering a fail-safe damper while decreasing weight and cost. Two hybrid damper designs are proposed in this thesis. The first one operates based on hydraulic damping as a source of passive damping, while the second design employs the eddy current damping effect to provide the passive damping part of the system. It is demonstrated that the introduction of the passive damping can reduce power consumption and weight in an active automotive suspension system. The ultimate objective of this thesis is to employ existing suspension system and damper design knowledge together with new ideas from electromagnetic theories to develop new electromagnetic dampers. At the same time, the development of eddy current dampers, as a potential source for passive damping element in the final hybrid design, is considered and thoroughly studied. For the very first time, the eddy current damping effect is introduced for the automotive suspension applications. The eddy current passive damper, as a stand-alone unit, is designed, modeled, fabricated and successfully tested. The feasibility of using passive eddy current dampers for automotive suspension applications is also studied. The structure of new passive eddy current dampers is straightforward, requiring no external power supply or any other electronic devices. Proposed novel eddy current dampers are oil-free and non-contact, offering high reliability and durability with their simplified design. To achieve the defined goals, analytical modeling, numerical simulations, and lab-based experiments are conducted. A number of experimental test-beds are prepared for various experimental analyses on the fabricated prototypes as well as off-the-shelf dampers. Various prototypes, such as eddy current and electromagnetic dampers, are manufactured, and tested in frequency/time domains for verification of the derived analytical and numerical models, and for proof of concept. In addition, fluid and heat transfer analyses are done during the process of the feasibility study to ensure the durability and practical viability of the proposed hybrid electromagnetic dampers. The presented study is only a small portion of the growing research in this area, and it is hoped that the results obtained here will lead to the realization of a safer and more superior automotive suspension system

Machine learning-based stocks and flowsmodeling of road infrastructure

This paper introduces a new method to account for the stocks and flows of road infrastructure at the national level based on material flow accounting (MFA). The proposed method closes some of the current shortcomings in road infrastructures that were identified through MFA: (1) the insufficient implementation of prospective analysis, (2) heavy use of archetypes as a way to represent road infrastructure, (3) inadequate attention to the inclusion of dissipative flows, and (4) limited coverage of the uncertainties. The proposed dynamic bottom-up MFA method was tested on the Norwegian road network to estimate and predict the material stocks and flows between 1980 and 2050. Here, a supervised machine learning model was introduced to estimate the road infrastructure instead of archetypical mapping of different roads. The dissipation of materials from the road infrastructure based on tire–pavement interaction was incorporated. Moreover, this study utilizes iterative classified and regression trees, lifetime distributions, randomized material intensities, and sensitivity analyses to quantify the uncertainties

Real-time reversible tunable elasticity in cellular solids via electromagnetic actuation

The ability for reversible, real-time control of elastic moduli in solids can find significant application in advanced mechanical components, protective structures, and biomedical devices. Here, we propose a novel concept for controlling the linear and nonlinear elastic properties of cellular structures via electromagnetically triggered mechanisms in the cellular solid. Three structural systems with orthotropic material properties were proposed and studied numerically, experimentally, and analytically. Using the proposed concept, the elastic modulus can be controlled over two to four orders of magnitude. The Poisson ratio of the isotropic structure can be varied from 0 to 0.5 continuously. The adjustments over nonlinear elastic (i.e., buckling) behavior of the structure are achieved by activation of supplementary cell walls in the lattice through electromagnetic actuation. Magnetic actuation will hamper the first symmetrical buckling pattern of the structure and force the structure to buckle according to a higher buckling pattern with smaller sinusoidal wavelength in the cell walls. The uniaxial buckling strength of the structure was tuned over two orders of magnitude

Estimation of Norwegian Asphalt Surfacing Lifetimes Using Survival Analysis Coupled with Road Spatial Data

Combinations of different factors and their relative importance have a mixed effect on the longevity of pavements, which are essential to be understood to enhance long-term maintenance planning. This study used spatial road data from Norway followed by integrating temporal-spatial and statistical analyses to show a potential approach to estimate the lifetimes of asphalt surfacing. For the statistical part, a stratified Cox proportional hazard model was used to understand the relationship between longevity of surface mixtures and different factors, while avoiding having predefined assumptions rooted in deterministic modeling. In addition, rutting was used as the response variable to determine distress-specific asphalt surfacing lifetimes and to handle censored data. Inclusion of rutting as the response variable showed that the median technical lifetime of asphalt surfacing is about 2\ua0years shorter than that of the maintenance activity records. The results showed the significance of each covariate; however, aggregate nominal maximum size and heavy traffic volume were consistently the significant covariates across the studied traffic classes. In addition, the results were fitted to reference categories in each covariate to show a practical approach to interpret absolute values of lifetimes from a survival table

Regionalized environmental impacts of construction machinery

Purpose: This study aims to establish a regionalized environmental impact assessment of construction machinery equipped with diesel engines certified by the European emission standard Stage V, and operated in cold climatic zones in Europe. Method: The study quantifies potential environmental impacts associated with construction machinery over the entire lifecycle, from extraction of materials to the end-of-life. For the operation phase, a meso-level emission accounting method is applied to quantify tailpipe emissions for certain subcategories of construction machinery. This is achieved by determining the operational efficiency of each machine in terms of effective hours. The quantified emission data are then adjusted based on engine deterioration models to estimate the rate of increase in emissions throughout the lifetime of each machine. Finally, the CML impact assessment method is applied to inventory data to quantify potential environmental impacts. Results: The study shows that tailpipe emissions, which largely depend on an engine’s fuel consumption, had the largest contribution to environmental impacts in most impact categories. At the same time, there was a positive correlation between the operation weight and the impacts of the machinery. Also, machinery with similar operation weight had relatively similar impact patterns due to similar driving factors and dependencies. In addition, network, sensitivity, and uncertainty analyses were performed to quantify the source of impacts and validate the robustness of the study. Results of the sensitivity analysis showed that the responsiveness of the studied systems is very sensitive to changes in the amount of fuel consumption. In addition, the uncertainty results showed that the domain of uncertainty increased as the operation weight subcategory of machinery increased. Conclusion: This study extends previous work on the life cycle assessment (LCA) of construction machinery, and the methodology developed provides a basis for future extension and improvement in this field. The use of effective hours as the unit of operational efficiency helps to resolve uncertainties linked to lifetime and annual operation hours. Also, the obtained results can be of use for decision support and for assessing the impacts of transition from fossil fuels to alternative fuel types

SpiderWeb honeycombs

A new class of hierarchical fractal-like honeycombs inspired by the topology of the “spiderweb” were introduced and their small and large deformations were investigated analytically, numerically, and experimentally. Small deformation elasticity results show that the isotropic in-plane elastic moduli (Young’s modulus and Poisson’s ratio) of the structures can be controlled over several orders of magnitude by tuning dimension ratios in the hierarchical pattern of spiderweb, and the response can vary from bending to stretching dominated. In large deformations, spiderweb hierarchy postpones the onset of instability compared to stretching dominated triangular honeycomb (which is indeed a special case of the proposed spiderweb honeycomb) and exhibits hardening behavior due to geometrical nonlinearity. Furthermore, simple geometrical arguments were obtained for large deformation effective Poisson’s ratio of first-order spiderweb honeycombs, which show good agreement with numerical and experimental results. Spiderweb honeycombs exhibit auxetic behavior depending on the nondimensional geometrical ratio of spiderweb

Propuesta de un método para evaluar los factores de imitación de marca

Brand imitation is an approach for new brands to be successful in the market; on the other hand, it can be destructive for developed brands by incurring heavy financial losses. Many studies have investigated imitation and its effective factors. The present paper studies effective factors of imitation and also ranks them through expert judgments. We use rough numbers properties to rank the factors. In so doing, three groups of experts, based in Iran, were asked to rank the factors that affect brand imitation. The ranking process was implemented by Rough-TOPSIS method. Also, the authors apply Fuzzy-TOPSIS method and findings were compared. This study recognizes important factors that affect brand imitation and rank them according to the significance level. Results emphasize that legislation is the most important factor that can prevent brand imitation and counterfeit. This ranking helps companies to improve specifications in order to obtain security for their brands.La imitación de marca es un enfoque para que las nuevas marcas tengan éxito en el mercado; por otro lado, puede ser destructiva para las marcas desarrolladas al incurrir en grandes pérdidas financieras. Muchos estudios han investigado la imitación y sus factores de efectividad. El presente artículo estudia los factores de efectividad de la imitación y también los clasifica a través de juicios de expertos. Usamos propiedades de números aproximados para clasificar los factores. Al hacerlo, se pidió a tres grupos de expertos, radicados en Irán, que clasificaran los factores que afectan la imitación de la marca. El proceso de clasificación fue implementado a través del método Rough-TOPSIS. Además, los autores aplican el método Fuzzy-TOPSIS y se compararon los resultados. Este estudio reconoce los factores importantes que afectan la imitación de marca y los clasifica según el nivel de significación. Los resultados enfatizan que la legislación es el factor más importante que puede prevenir la imitación de marca y la falsificación. Esta clasificación ayuda a las empresas a mejorar las especificaciones con el fin de obtener seguridad para sus marcas