Subadditivity and Contestability in the Postal Sector: Theory and Evidence

Several studies have been conducted to analyze whether a regulation of the postal sector as a monopoly is actually efficient by examining its cost structure. The authors detected significant scale economies only in the delivery function and hence demonstrated a necessity for competition in the upstream operations. The primary purpose of this paper is to summarize the basic conditions of natural monopoly theory and to review the approaches and results of the studies dealing with this topic. Despite the importance of contestability in this context, previous literature concentrates only on the subadditivity aspect. The existence of economies of scale does not inevitably justify a governmental maintenance of the monopoly if the market is contestable. In this respect, further research is needed in order to account for contestability.Postal Sector, Scale Economies, Subadditivity, Contestability

Experimental test of the consequences of host-parasite coevolution of the nematode Caenorhabditis elegans and its microparasite Bacillus thuringiensis

Host-parasite coevolution, or the evolution of host defence and parasite counter defence is predicted to associate with high selection dynamics that are crucial for the evolution of a number of biological processes, such as fitness traits related to bothantagonists and the mechanisms generating fast genetic changes. The main objective of my PhD thesis is to enhance our understanding of host-parasite coevolution as a major selective force. Hence I addressed the complex set of the predicted evolutionary consequences that are unique to host-parasite coevolution, at both the phenotypic and molecular level, for both antagonists, and across time. I used an experimental evolution approach - under controlled laboratory conditions - using the nematode Caenorhabditis elegans as a model host, and the bacterium Bacillus thuringiensis as a model parasite. I optimized the selection protocol and multiple phenotypic measurements to compare the differences in the evolutionary outcomes between coevolution, one-sided evolution, and control conditions. After 28 host generations, I found that coevolution (i) causes reciprocal changes in both host resistance and pathogen virulence, (ii) affects their life history trade-offs, and (iii) produces patterns that are clearly different from one-sided adaptation and control conditions (Chapter I). In general the consequences of host-parasite coevolution were more pronounced in the parasite except for the patterns of temporal adaptations (Chapter I). Moreover, my results gave insights into the role of males and outcrossing in the evolution of the studied host-parasite interactions. I found an opposing interference of two selective forces that act either on the inter-species level (i.e., the high selective pressure that the antagonists exert on each other; Red Queen theory) or on the intra-species level (i.e., the differences in immunity among host genders; Bateman’s principle of immunity). Males showed higher pathogen susceptibility than hermaphrodites, thus limiting but not abolishing the potential for outcrossing and recombination for fast host adaptation (Chapter II). Finally, for the parasite, we identified genetic changes in: (i) genotype frequency, (ii) the presence or combination of cry toxins, and (iii) the presence and frequency of single nucleotide polymorphisms (SNPs). The molecular analysis was done across three time points over all replicate populations. We found that the overall parasite evolution is dominated by clonal selection followed or combined with the spread of individual mutations (Chapter III)

DEVELOPING ‘URBAN JUNGLE’ AS AN INTEGRATED MODEL OF SURVIVAL: Learning from Nature in War Zones

ConCave Ph.D. Symposium 2020: Divergence in Architectural Research, March 5-6, 2020, Georgia Institute of Technology, Atlanta, GA.This paper explores the relationship between conflict in the urban environment and natural systems of resiliency found in forests and jungles. Studying the different accounts of inhabitants of cities under siege during the Syrian Civil war, indicates that various sustainable practices were implemented within the built environment that helped inhabitants survive the devastating process. The innovative, circular economy allowed the inhabitants to survive their plight and lessened the intended effects of the destructive sieges. Drawing parallels with how forests and jungles utilize different natural systems, such as mycorrhizal networks, to increase resiliency, many lessons are inferred about sustainable resource management and efficient allocation in the face of different threats. The “Urban Jungle” is thus synthesized as a model that attempts to augment and maximize the practices inhabitants had devised through mimicking the model found in the natural jungle. Applying this model to conflict zones allows the evolution of survival tactics into a form of insurgent resilience, with wider socio-political ramifications on the survivability of the inhabitants, their political will, the effectiveness of the conflict, and sieges as a political tool

Design and Behavior of Steel Delta Girders

In steel structures, I-sections are commonly used for beams and columns. These cross-sections usually lack lateral rigidity and torsional stiffness. An effective method to improve their lateral rigidity and overall flexural resistance is to weld two inclined rectangular plates to the compression flange and the compression portion of the web of hot-rolled or welded I-section to form what is known as a Delta girder. This mixed cross-section, i.e., cross-section composed of an open profile attached to a closed profile, can provide enhanced torsional stiffness and hence noticeably higher lateral-torsional buckling (LTB) capacity for the beam. While Delta girders can be used for any beams, their main applications are the design of crane runway and bridge beams and strengthening of existing beams. The main objectives of this dissertation are to study the static behavior of these girders and to provide a set of design equations for their nominal flexural and shear capacities. The research includes deriving closed-form equations for the cross-section properties of Delta girders. These equations are then verified against solutions obtained numerically. Using these cross-section properties, the theoretical lateral-torsional buckling capacity of Delta girders are determined and compared against results obtained from a finite element (FE) analysis. The results show that the theoretical LTB equation derived for general monosymmetric sections can be applied to these Delta girders. Additionally, it is shown that a simplified expression for the coefficient of monosymmetry βx derived for I-sections can be used in the computation of the elastic LTB capacity of Delta girders. A parametric study is then performed based on elastic LTB capacity to demonstrate the effectiveness of Delta girders in achieving a favorable capacity-to-weight ratio when compared to standard I-section members. A refined three-dimensional (3D) nonlinear inelastic FE models are then developed to examine the capacity of simply-supported Delta girders under uniform bending and pure shear. The models take into considerations the effects of initial geometrical imperfections and residual stresses on the behavior of Delta girders. The FE model and the modeling techniques used are verified against the experimental result of a test beam that failed by inelastic LTB. The analysis covers a comprehensive range of Delta girder dimensions based on the dimensions of standard hot-rolled European H- and I-sections. A sensitivity study on the effects of using reduced imperfections magnitudes shows up to 18.2% increase in the LTB capacity of the girder. Based on the FE LTB simulation results, it is shown that the buckling curve in the AISC (2016a) specifications overestimates the buckling capacity of Delta girders by an average of 9% and a maximum value of 21%. On the other hand, buckling curves “a” and “b” for rolled sections or equivalent welded sections case in the EuroCode 3 (2005) for Delta girders with d⁄bc ≤2 and d⁄bc \u3e2, respectively, provide an average difference of only 2% and a maximum difference of 7% in comparison to the FE results. Hence, these two curves are recommended for the LTB design of Class 1 (compact) Delta girders. Additionally, design recommendations are provided for selecting the proper delta stiffeners dimensions based on the cross-section geometries of the corresponding I-sections. Shear capacity equations for Class 1 (compact) Delta girders are proposed based on FE simulation results. The equations provide the option of selecting a conservative value that ignores strain hardening in the cross-section or a value that allows for some strain hardening to occur. In comparison to I-sections, the Delta girders analyzed in this study show an increase in shear capacity in the range of 41% to 89%. Furthermore, it is shown that in contrast to I-sections, yielding is a gradual process in Delta girders due to the presence of a non-uniform elastic shear stress distribution in the cross-section

International Education Policymaking: A Case Study of Ontario’s Trillium Scholarship Program

This paper explores Ontario’s international education policy landscape through illuminating the discursive struggles to define international student funding policies, in particular the international doctoral students’ Trillium Scholarship. Adopting Hajer’s (1993, 2006) Discourse Coalition Framework, the study engages with three research questions: What paved the way to this funding policy? Who were the actors engaged in this policy landscape? How has the argumentation over this policy influenced the international education policy context in Ontario? Argumentative discourse analysis was used to analyze three data sources: news articles, policy documents, and interviews. Two storylines were identified: international student funding is desirable and beneficial to Ontario versus Ontario first. Whereas the first storyline achieved hegemony, the second succeeded in bringing discourses of protectionism to the forefront influencing the government’s future engagement with international student funding. The paper ends with three observations on Ontario’s international education policy landscape. This study contributes to our understanding of how international student funding can be highly political and influenced by non-education policy spaces and discourses

International Education as Policy: A Discourse Coalition Framework Analysis of the Construction, Context, and Empowerment of Ontario\u27s International Education Storylines

This study aims to examine the international education (IE) policy-making context in Ontario for the period from 2005 to mid-2017 while also taking into account the announcement of the new policy document Ontarios International Postsecondary Education Strategy 2018. It sets out to answer three research questions: (a) How is international education constructed as a policy discourse in the postsecondary sector in Ontario? (b) Who are the policy actors who are contributing to the postsecondary international education policy-making process in Ontario? and (c) What role do they play in influencing IE policy and empowering and silencing different discourses? To answer these research questions, this study adopts Maarten Hajers Discourse Coalition Framework (DCF) and steps of doing argumentative discursive analysis (2006). Data sources included IE stories in the three highest-circulation newspapers in Ontario (415 articles); 23 interviews with policy actors, and 195 policy documents. Whereas policy studies employing DCF have typically identified oppositional storylines, the findings of this study reveal one dominant storyline: Internationalize. All discourses agree, to varying degrees, that IE is desirable and beneficial to the postsecondary education sector and Ontario. However, within the overarching Internationalize storyline, three storylines emerge: (a) Internationalize, it is good for the economy (Economy); (b) Internationalize, yet manage its risks (Risks); (c) Internationalize, it is Canadas gateway to the world (Gateway). The Economy storyline achieves hegemony as it succeeds in imposing its logic and ways of deliberation on the IE policy landscape (structuration) and is translated into institutional practices and policies (institutionalization). The study also reveals a shifting terrain in the IE policy landscape with the emergence of a new Regulate IE storyline, which has succeeded in introducing regulation and accountability discourses and reframing the hegemonic Economy storyline. By moving away from the state and focusing on storylines, this study reveals the fragmentation of the IE policy landscape and exposes actors from diverse scales, levels, disciplines, and contexts; all of whom contribute to the construction of IE and its related policies. One of the main findings of this study is the role of the media in building the IE narrative and mobilizing storylines. This research contributes to our understanding of the economic aspect of internationalization, which goes beyond discourses of neo-liberalism, and argues against the traditional binary categorizations of socio-cultural and educational versus economic internationalization. On a theoretical level, the study outlines the strengths of DCF and unsettles its conceptualization of collective and individual discursive agencies

Development of a renewable hybrid power plant with extended utilization of pumped storage unit equipment

The scheme of a renewable hybrid power plant with the extended use of the installed equipment of the pumped storage unit for the conversion of the photovoltaic and wind generators direct current to the alternating one is proposed. The scheme is based on existing components with widely used proven technology. To output the power of solar and wind generators to the grid and for DC to AC conversion, a synchronous generator of the pumped storage unit is used in addition to grid inverters. An induction motor, powered through a variable frequency drive from a common DC bus, is used together with a hydraulic turbine to rotate the generator. In addition, batteries and capacitors banks are connected to the DC bus. The possibility of using various types of electric machines to drive a synchronous generator is analyzed and the preference of an induction motor is shown. The response of an induction motor to rotational speed fluctuations is modeled and its capability to participate in the network frequency regulation is shown. With the example of a typical daily load and generation profile, it is shown that the proposed solution for DC to AC conversion has an efficiency close to that of the grid inverter. The proposed scheme of the hybrid power plant can increase the reliability of renewable energy sources and the stability of the network frequency. This is achieved due to increasing the inertia of the rotating masses in the power system, the power factor control capabilities of the synchronous generator and the proper response of induction motor to rapid fluctuations of the rotation speed. The creation of such hybrid power plants opens the way for a further increase in the share of renewable energy sources in the power system.Запропоновано схему гібридної відновлюваної електричної станції з розширеним використанням встановленого обладнання гідроакумулюючого блока для перетворення постійного струму фотоелектричних та вітрових генераторів в змінний. Схема базується на наявних компонентах з широко використовуваною відпрацьованою технологією. Для видачі потужності та перетворення постійного струму сонячних та вітрових генераторів в змінний окрім мережевих інверторів використовується синхронний генератор гідроакумулюючого блоку. Для обертання генератора крім гідротурбіни також використовується асинхронний двигун, підключений через частотно-регульований привод до загальної шини постійного струму станції. Крім того, до шини постійного струму підключені електрохімічні акумулятори і батареї конденсаторів. Проаналізовано можливість використання різних типів електричних машин для приводу синхронного генератора і показано перевагу асинхронного двигуна. Змодельовано реакцію асинхронного двигуна на коливання швидкості обертання і показано його здатність брати участь в регулюванні частоти мережі. На прикладі типового добового графіка навантаження і генерації показано, що запропоноване рішення по перетворенню постійного струму в змінний має ККД, близький до ККД мережевого інвертора. Запропонована схема гібридної станції дозволяє підвищити надійність роботи відновлюваних джерел енергії і стабільність частоти мережі. Це досягається завдяки збільшенню інерції обертових мас в енергосистемі, можливості управління коефіцієнтом потужності синхронного генератора і властивій асинхронному двигуну реакції на коливання швидкості обертання. Створення таких гібридних станцій відкриває шлях до подальшого збільшення частки відновлюваних джерел в енергосистемі