In the energy field, the decisions need to take into consideration several factors such as the needs of the population, the environment, suitability, capital cost, sustainability, political goals and the actors involved, with their interests and preferences. The lack of homogeneity in all the factors that must be consider makes it necessary to design a process that guides the analysis process of any type of decision-maker. Decision analysis methods have been developed to aid decision-makers identify a problem, determine the criteria to be consider and their importance, recognize the stakeholders that need to be involved and pose the different alternatives to resolve or to best address the problem. These techniques range from simple to more mathematically oriented ones, from single criterion evaluation to multiple criteria, and from purely qualitative or quantitative to mixed techniques. Within the field of decision analysis, multi-criteria techniques are better suited to aid in decision situations in the energy field as these decisions require several considerations beside economic ones. This thesis uses theories and notions of decision analysis to construct a framework to be used in any energy related decision situations by non-experts. The framework tackles common challenges faced by multi-criteria decision analysis methods, including the identification of stakeholders and decision-makers, the aggregation of various decision-makers, preferences and heterogeneous inputs, and the selection of suitable criteria, alternatives and methods.

The paper investigates how including the distribution of wealth changes the demand effects of redistributing functional income. It develops a model with an endogenous wealth distribution and shows that the endogenous rise in wealth inequality resulting from a redistribution towards profits weakens the growth effects of this redistribution. Consequently, a wage-led regime becomes more strongly wage-led. A profit-led regime on the other hand becomes less profit-led and there may even be a regime switch - in this case the short-run profit-led economy becomes wage-led in the long run due to the endogenous effects of wealth inequality. The paper thereby provides a possible explanation for the instability of demand regimes over time. / Series: Ecological Economic Papers

Thesis (M.A. in applied economics)--Washington State University, May 2007. / Includes bibliographical references (p. 71-73).

Aggregate properties influence different aspects of asphalt pavement performance. Aggregate polishing characteristics are directly related to pavement surface frictional properties and thus to skid resistance. Aggregate resistance to degradation (abrasion and breakage) is another important property that influences pavement performance. Aggregate degradation could take place during production due to plant operations and during compaction, leading to change in aggregate characteristics and mix properties. In addition, aggregate resistance to degradation is important in mixes such as Stone Matrix Asphalt (SMA) and Open Graded Friction Course (OGFC) that rely on stone-to-stone contacts among coarse aggregates. Some aggregates in these mixes fracture due to the high stresses at contact points. Many test methods exist for measuring aggregate polishing and degradation, but a critical review of these methods reveals that they suffer from being time consuming, are unable to differentiate between aggregates with distinct resistance to polishing, or unable to differentiate between aggregate resistance to abrasion and breakage. New methodologies are needed to give better assessment of aggregate resistance to polishing, abrasion, and breakage. The thesis presents the development of new methods for measuring aggregate resistance to polishing, abrasion, and breakage. These methods rely on measurements using the Aggregate Imaging System (AIMS) and Micro-Deval. The new method for measuring aggregate resistance to polishing monitors change in aggregate texture as a function of polishing time. As such, it provides the initial texture, rate of polishing, and final texture. The new method for measuring aggregate degradation is capable of distinguishing between breakage and abrasion. In this method, abrasion is defined as the reduction in aggregate angularity, while breakage is defined by fracture of particles. The new methods are shown to be rapid and accurate, and they require reasonable training. Since both AIMS and Micro-Deval are used in the new methods, it was necessary to evaluate the repeatability of these two methods. Measurements using two AIMS units and two Micro-Deval machines were used to assess the variability. There was no statistical difference between the measurements of the two AIMS units or between the measurements of the two Micro-Deval units.

Aggregate extraction has been identified as one of the most contentious land-uses in Southern Ontario. The siting or expansion of aggregate operations is often met with vehement debate from concerned members of the public, local municipalities, and additional parties who have various reasons to be opposed to aggregate extraction operations. “Aggregate wars” have now become a common planning challenge in a number of aggregate rich municipalities in Ontario. Due to a legacy of poor rehabilitation practices, aggregate site rehabilitation has been identified as one of the most serious problems plaguing pit and quarry developments. Aggregate site rehabilitation plays and essential role in preparing the land for its sequential land-use and is the primary mechanism for the mitigation of adverse environmental and social impacts caused by the extraction process. Using a mixed-methods research approach, this study aimed to determine the rate and quality of aggregate site rehabilitation occurring in Ontario for the time period of 1992-2011. This was completed using an assessment of production statistics and a sample of rehabilitation plans. In addition, interviews with representatives from key actor groups were conducted to strengthen the base for evaluating the effectiveness of the current policy framework to ensure the adequate rehabilitation of aggregate sites. Results from this study indicate that progressive rehabilitation efforts are falling short and a net gain in disturbed land is occurring each year. More research, in the form of field studies and long-term monitoring initiatives, is needed to permit a better assessment of the quality of rehabilitation occurring. Findings from this study illustrate that the current rate of aggregate site rehabilitation occurring in Ontario is not enough to moderate adverse environmental and social impacts. Changes are needed to the current policy framework in order to address this problem. Four policy recommendations are suggested: to set a maximum for disturbed areas at operating aggregate sites, to re-implement a security deposit type model, to introduce citizen advisory committees in the aggregate site management process, and to tie site and rehabilitation plans to predetermined timelines. An analysis of aggregate site rehabilitation prior to 1992 requires further research

Cell shape is important to understanding the mechanics of three-dimensional (3D) cell aggregates. When an aggregate of embryonic cells is compressed between parallel plates, the cell mass and the cells of which it is composed flatten. Over time, the cells typically move past one another and return to their original, spherical shapes, even during sustained compression, although the profile of the aggregate changes little once plate motion stops. Although the surface and interfacial tensions of cells have been attributed to driving these internal movements, measurements of these properties have largely eluded researchers. Here, an existing 3D finite element model, designed specifically for the mechanics of cell-cell interactions, is enhanced so that it can be used to investigate aggregate compression. The formulation of that model is briefly presented and enhancements made to its rearrangement algorithms discussed. Simulations run using the model show that the rounding of interior cells is governed by the ratio between the interfacial tension and cell viscosity, whereas the shape of cells in contact with the medium or the compression plates is dominated by their respective cell-medium or cell-plate surface tensions. The model also shows that as an aggregate compresses, its cells elongate more in the circumferential direction than the radial direction. Since experimental data from compressed aggregates are anticipated to consist of confocal sections, geometric characterization methods are devised to quantify the anisotropy of cells and to relate cross sections to 3D properties. The average anisotropy of interior cells as found using radial cross sections corresponds more closely with the 3D properties of the cells than data from series of parallel sections. A basis is presented for estimating cell-cell interfacial tensions from the cell shape histories they exhibit during the cell reshaping phase of an aggregate compression test.

Cell shape is important to understanding the mechanics of three-dimensional (3D) cell aggregates. When an aggregate of embryonic cells is compressed between parallel plates, the cell mass and the cells of which it is composed flatten. Over time, the cells typically move past one another and return to their original, spherical shapes, even during sustained compression, although the profile of the aggregate changes little once plate motion stops. Although the surface and interfacial tensions of cells have been attributed to driving these internal movements, measurements of these properties have largely eluded researchers. Here, an existing 3D finite element model, designed specifically for the mechanics of cell-cell interactions, is enhanced so that it can be used to investigate aggregate compression. The formulation of that model is briefly presented and enhancements made to its rearrangement algorithms discussed. Simulations run using the model show that the rounding of interior cells is governed by the ratio between the interfacial tension and cell viscosity, whereas the shape of cells in contact with the medium or the compression plates is dominated by their respective cell-medium or cell-plate surface tensions. The model also shows that as an aggregate compresses, its cells elongate more in the circumferential direction than the radial direction. Since experimental data from compressed aggregates are anticipated to consist of confocal sections, geometric characterization methods are devised to quantify the anisotropy of cells and to relate cross sections to 3D properties. The average anisotropy of interior cells as found using radial cross sections corresponds more closely with the 3D properties of the cells than data from series of parallel sections. A basis is presented for estimating cell-cell interfacial tensions from the cell shape histories they exhibit during the cell reshaping phase of an aggregate compression test.

The aim of this research is to produce a model allowing me to estimate the credit risks in the aggregate and the sectors levels of the Swedish economy in response to the evaluation of key macroeconomic variables. In order to estimate the credit risk models for the Swedish economy, one-factor models were used and the employed data were covering the period from 2003 to 2011. One factor models’ estimations for the sectors facilitate a comparison of default rates’ determiners between different sectors. The analyze part of the thesis starts with the estimation of the credit risk model at the aggregate economy level and it follows by the estimation of the models for different sectors. Ten different sectors are analyzed and for all sectors, the default rate models are produced. Furthermore, the paper presents some examples of applying the estimated models to macro stress testing. The findings demonstrate that in the transport and in the sector others, the most significant macroeconomic indicators were GDP, interest rates and repo rates. But, in all other sectors: GDP, interest rates and inflation rates showed the highest significant results. All coefficients were significant at the 5 % confidence level either in aggregate level or in sectors level. The interest rates showed positive relations with the default rates while the GDP and the inflation rates showed opposite relations. Reciprocal analyzes of the sectors indicated that compared to other sectors, the default rates in the financial sector strongly depended on the GDP and in the construction sector it weakly depended on inflation rates. In addition, the credit risks were varying between the sectors. At the education and the sector others, default rates were low, fluctuated between 0 and 0.05%. In contrast, at the manufacturing, the wholesale, the transportation, and the finance sectors the default rates were very high. It fluctuated between 0.03% and 0.16%. Finally, estimated models were used for the sensitive analyze of default rates by creating shocks over the independent variables. So, these calculations provided that, the default rates in financial activities sector were the most sensible sector during the shock at the GDP and the default rates in the construction sector were the most insensible ones during the shock at the interest rates and the inflation rates. To conclude, the results of this thesis can help understand the relationship between credit risk and macroeconomic indicators. This research provides important findings on how the macroeconomic indicators influence the default rates of Swedish economy either at the aggregate or at the sectors level. The calculated models can be used for the default rates’ prediction or stress testing.

The aggregate base layer is a vital part of the flexible pavement system. Unlike rigid pavements, the base layer provides a substantial contribution to the load bearing capacity in flexible pavements, and this contribution is complex: stress dependent, moisture dependent, particle size dependent, and is anisotropic in nature. Furthermore, the response of the aggregate layer in the pavement structure is defined not only by resilient properties of the base layer but also by permanent deformation properties of the aggregate layer. Before the benefits of revolutionary changes in the typical pavement structures, such as deep unbound aggregate base (UAB) layers under thin hot mix asphalt surfaces and inverted pavement systems can be justified, an accurate assessment of the UAB is required. Several researchers identified that in order to properly assess the contribution of the UAB in the pavement structure, it is necessary to consider not only the vertical modulus but also the horizontal modulus as this substantially impacts the distribution of stresses within the pavement structure. Anisotropy, which is defined as the directional dependency of the material properties in unbound granular bases, is inherent even before the aggregate layer is subjected to traffic loads due to random arrangement of particles upon compaction. Distribution of particle contacts is dominated by the geometry of the aggregates as well as the compaction effort at the time of construction. Critical pavement responses and therefore performance of flexible pavements are significantly influenced by the level of anisotropy of aggregate layers. There are several ways to characterize the level of anisotropy in unbound aggregate systems. Previous research at Texas A&M University suggests functions of fitting parameters in material models (kvalues) as characterizers of the level of anisotropy. In the realm of geotechnical engineering, the ratio of the horizontal modulus to vertical modulus is commonly referred to as the level of anisotropy. When the vertical and horizontal moduli are equal, the system is isotropic, but when they differ, the system is anisotropic. This research showed that the level of anisotropy can vary considerably depending on aggregate mix properties such as gradation, saturation level, and the geometry of the aggregate particles. Cross anisotropic material properties for several unbound and stabilized aggregate systems were determined. A comprehensive aggregate database was developed to identify the contribution level of aggregate features to the directional dependency of material properties. Finally a new mechanistic performance protocol based on plasticity theory was developed to ensure the stability of the pavement foundations under traffic loads.

The effects of using alkali-silica reaction (ASR) affected recycled concrete aggregate (ASR-RCA) in hot mix asphalt (HMA) were investigated in this study. Dilatometer and modified beam tests were performed to determine the possibility of new ASR occurring in reactive aggregates within the HMA or re-expansion of existing gel. The Lottman test and micro-calorimeter were used to determine the moisture susceptibility of HMA made with ASR-RCA. A differential scanning calorimeter (DSC) with thermogravimetric analysis (TGA) was used to evaluate the drying of an artificial gel and x-ray diffraction (XRD) was used to check for the potential presence of gel in the filler fraction of the ASR-RCAs. Micro-deval and freeze-thaw tests were evaluated for their potential to indicate the presence of excess micro-cracks or ASR gel. Expansion testing indicated that both ASR-RCAs were still reactive with 0.5 N NaOH solution saturated with calcium hydroxide (CH) at 60 degrees C. Dilatometer testing of HMA specimens in NaOH CH solution at 60 degrees C indicated a reaction between the asphalt binder and the solution, but little, if any, ASR. The lack of expansion in the modified beam test supports the binder-solution interaction. However, dilatometer testing in deicer solution at the same temperature indicated that some ASR may have occurred along with the primary binder-solution interaction. The volume change characteristics associated with the binder-solution interaction with and without ASR was supported by the change in pH and alkali concentration of the test solution. DSC/TGA testing indicated that the artificial gel dehydrated at approximately 100 degrees C. XRD analysis of the filler indicated that some gel may have accumulated in this fraction. Moisture damage testing indicated good resistance to moisture damage by HMA mixtures made with ASR-RCA especially compared to a virgin siliceous aggregate. Micro-deval and freeze-thaw tests can detect the presence of micro-cracks due to ASR in ASR-RCAs as higher mass loss than the virgin aggregate. The potential distress mechanisms that may occur when using ASR-RCA in an HMA pavement were identified. Results obtained using accelerated laboratory conditions were extrapolated based on anticipated field conditions. Guidelines for the mitigation of potential distresses in HMA made with ASR-RCA are presented.