Size-dependent material responses observed at fine length scales are receiving growing attention due to the need in the modeling of very small sized mechanical structures. The conventional continuum theories do not suffice for accurate descriptions of the exact material behaviors in the fine-scale regime due to the lack of inherent material lengths. A number of new theories/models have been propounded so far to interpret such novel phenomena. In this dissertation a few enriched-continuum theories - the adhesive contact mechanics, surface elasticity and strain gradient elasticity - are employed to study the mechanical behaviors of a semi-infinite solid induced by the boundary forces. A unified treatment of axisymmetric adhesive contact problems is developed using the harmonic functions. The generalized solution applies to the adhesive contact problems involving an axisymmetric rigid punch of arbitrary shape and an adhesive interaction force distribution of any profile, and it links existing solutions/models for axisymmetric non-adhesive and adhesive contact problems like the Hertz solution, Sneddon's solution, the JKR model, the DMT model and the M-D model. The generalized Boussinesq and Flamant problems are examined in the context of the surface elasticity of Gurtin and Murdoch (1975, 1978), which treats the surface as a negligibly thin membrane with material properties differing from those of the bulk. Analytical solution is derived based on integral transforms and use of potential functions. The newly derived solution applies to the problems of an elastic half-space (half-plane as well) subjected to prescribed surface tractions with consideration of surface effects. The newly derived results exhibit substantial deviations from the classical predictions near the loading points and converge to the classical ones at a distance far away from those points. The size-dependency of material responses is clearly demonstrated and material hardening effects are predicted. The half-space contact problems are also studied using the simplified strain gradient elasticity theory which incorporates material microstructural effects. The solution is obtained by taking advantage of the displacement functions of Mindlin (1964) and integral transforms. Significant discrepancy between the current and the classical solutions is seen to exist in the immediate vicinity of the loading area. The discontinuity and singularity exist in classical solution are removed, and the stress and displacement components change smoothly through the solid body.

The primary objective of this research program was to investigate the effective modulus of elasticity and shear modulus of brick masonry walls under lateral load, and to to justify using the Jaeger and Mufti method to calculate the effective modulus of elasticity and shear modulus of brick masonry walls. The experimental program involved the testing of three unreinforced brick masonry walls under in-plane and vertical loads. Linear Variable Differential Transducers were used to record the horizontal and vertical displacements of the walls. The experimental results were used to evaluate the modulus of elasticity and the shear modulus of walls under flexure. The experimental results were compared to the finite element analysis results. It was found that the finite element analysis yields similar results to the experimental results. It was also found that the Jaeger and Mufti method to calculate effective modulus of elasticity and shear modulus of brick masonry walls is effective for design purposes.

The purpose of this research is to understand and explain the TFT LCD industry phenomenon of oversupply vs. shortage and its impacts on the prices and quantities of individual TFT LCD makers. Also, to look for any fixed effects (if any exist) due to specific company and due to specific time. We employ a fixed effect model to estimate impacts of individual traded quantity on price and impacts of individual price on traded quantity. Using the panel data covering 16 makers and 24 months, our results reveal that the TFT LCD panel is highly quantity inelastic of the traded price but greatly price elastic of the traded quantity. With regard to fixed effect, the empirical result reveals there were significant time effects of price for some periods of time while there were significant time effects of quantity for some sizes of panels. Supply and demand could be one of the factors determining the time effects. As to the company fixed effect, most of company fixed effects of quantity prices were found significant whereas company fixed effects of price were not. Market shares and country of origin can be significant factors determining the company fixed effect of quantity. Keywords: Panel Data, Fixed Effect Model, Quantity Elasticity, Price Elasticity, Company Fixed Effect, Time Fixed Effect, TFT LCD

Les systèmes déployés dans être testés pendant l’élasticité, ce qui entraîne plusieurs problématiques. D’abord, l’exécution d’un test pendant l’élasticité peut exiger de conduire le CBS dans une succession de comportements élastiques spécifiques, càd., une séquence d’ajout/retrait de ressources, qui nécessite des variations précises de la charge des requêtes envoyées au cloud. Seconde, certaines adaptations du CBS ne sont réalisées qu’à un moment précis, par exemple après un ajout de ressources et, par conséquent, leurs tests doivent être synchronisés avec des états spécifiques du CBS. Troisième, les testeurs doivent rejouer les tests pendant l’élasticité de manière déterministe afin de déboguer et corriger le CBS. Quatrième, la création des tests pendant l’élasticité est complexe et laborieuse dû au large nombre de paramètres, et à la particularité du cloud computing. Enfin, seulement quelques combinaisons de paramètres peuvent causer des problèmes au CBS, que les cas de test créés au hasard peuvent manquer, alors qu’un jeu de tests couvrant toutes les combinaisons possibles serait trop grand et impossible à exécuter. Dans cette thèse, nous abordons toutes ces problématiques en proposant plusieurs approches :1) une approche qui conduit les CBSs dans une suite de comportements élastiques prédéfinis, 2) une approche qui synchronise l’exécution des tests selon les états du CBS, 3) une approche qui permette la reproduction des tests pendant l’élasticité, 4) un langage spécifique à ce domaine (DSL, selon l’acronyme anglais) qui résume la mise en œuvre des tests pendant l’élasticité, 5) une approche qui génère des petits ensembles de tests pendant l’élasticité tout en révélant des problèmes liés à l’élasticité. / Systems deployed on elastic infrastructures deal with resource variations by adapting themselves, which may cause errors, or even degrade their performance. Therefore, we must test the Cloud-Based Systems(CBSs) throughout elasticity, which faces problematics. First, executing elasticity tests may require the lead of CBS throughout a specific elastic behavior, i. e.,sequence of resource changes, which depends on an accurate workload generation. Second, CBS adaptations occur at a precise moment, such as after a resource scale out, which requires to test them during a specific CBS states. Third, testers must re-execute elasticity tests in a deterministic manner to debug and fix the CBS. Fourth, implementing elasticity tests is complex and laborious given the wide possibility of parameters, and the peculiarity of cloud computing. Finally, specific combinations of parameters may cause the system issues, where random tests may miss such combinations, while a test set that covers all thecombinations may be large and impractical to execute. In this thesis, we tackle all these five problematics by proposing several approaches: 1) an approach to drive the CBS throughout preset elastic behaviors, 2) an approach to synchronize tests according to the CBS states, 3) an approach to enable reproducing elasticity testing, 4) a Domain Specific Language (DSL)-basedapproach to abstract the elasticity testing implementation, and 5) an approach to generate small sets of tests that reveal relevant elasticity-related issues.

The popularity of natural rubber as an important raw material was distorted in the post-World War Two period. It received heavy competition from synthetic rubber. The main purpose of this paper is to determine and to study supply elasticity and demand elasticity of natural rubber in the case of Malaysia. The main aim of analyzing the period since 1971 is that both price and quality competitiveness of Malaysian natural rubber have drastically improved. Therefore, in order for Malaysia to maintain her position as the leading producer and exporter of natural rubber in the world, supportive policies and incentives from the government would further enhance the prospects for improvements in this industry.

Understanding how car travel and ownership respond to income and fuel prices, and how that response varies between households is crucial for car use policies and forecasts. This thesis, consisting of two papers, aims to investigate this by estimating the intemporal income and fuel price elasticities of car use using micro registry panel data on all Swedish households from 1998 to 2018. In Paper I, the income and fuel price elasticities of vehicle kilometres travelled (VKT) is estimated for all Swedish households using a linear fixed effects model. In order to investigate how different groups respond, the elasticities are estimated by income group and municipality type. The effect of income and fuel prices on VKT is largest in the middle of the income distribution but is relatively stable across municipality types. The effect of fuel prices on VKT is largest in densely populated municipalities compared to rural municipalities. Moreover, it is shown that the income elasticity is underestimated if income variable is misspecified. Paper II utilises a discrete-continuous model accounting for the effect of income and fuel prices on car ownership. It is shown that income impacts car ownership and VKT conditional on car ownership of similar magnitude, while fuel prices primarily impact VKT conditional on car ownership. Furthermore, we also estimate the model on six partially overlapping sample periods and find that the income elasticity has decreased over time, while the absolute fuel price elasticity increased up until the early 2010s and decreased thereafter. / <p>2022-10-13: ISBN (PDF) has been added in the E-version.</p>

Understanding how car travel and ownership respond to income and fuel prices, and how that response varies between households is crucial for car use policies and forecasts. This thesis, consisting of two papers, aims to investigate this by estimating the intemporal income and fuel price elasticities of car use using micro registry panel data on all Swedish households from 1998 to 2018. In Paper I, the income and fuel price elasticities of vehicle kilometres travelled (VKT) is estimated for all Swedish households using a linear fixed effects model. In order to investigate how different groups respond, the elasticities are estimated by income group and municipality type. The effect of income and fuel prices on VKT is largest in the middle of the income distribution but is relatively stable across municipality types. The effect of fuel prices on VKT is largest in densely populated municipalities compared to rural municipalities. Moreover, it is shown that the income elasticity is underestimated if income variable is misspecified. Paper II utilises a discrete-continuous model accounting for the effect of income and fuel prices on car ownership. It is shown that income impacts car ownership and VKT conditional on car ownership of similar magnitude, while fuel prices primarily impact VKT conditional on car ownership. Furthermore, we also estimate the model on six partially overlapping sample periods and find that the income elasticity has decreased over time, while the absolute fuel price elasticity increased up until the early 2010s and decreased thereafter.

The housing market is one of the most important markets for many economic agents. Large differences in the local market across Sweden suggest regional heterogeneity, however. This study aims to answer if the price and income elasticities of demand for small houses vary between different types of Swedish municipalities. This answer is explored in the light of the central place theory and location theory to see if they follow a hierarchal structure across space. To test this empirically, the 290 municipalities were grouped based on the Swedish Association of Local Authority and Regions’ definitions and tested group-wise using a log-log fixed-effect average hedonic price model using data for 2013-2020. The main findings indicate some differences in the estimates of price and income elasticities between different types of municipalities, but mixing results whether they follow a hierarchal relationship. The conclusions changes depending on which scale one measure, which indicate how local the housing market is.

This dissertation consists of three chapters that estimate the elasticities regarding price and time in trade and household production. Chapters 1 and 2 estimate price elasticities. Chapter 1 estimates the one-factor-one-price elasticity of substitution (OOES)—or how the percentage change in the quantity of one good responds to the percentage change in the price (of itself or another good)—in an international trade context. Chapter 2 estimates the two-factor-one-price elasticity of substitution (TOES)—or the difference of percentage changes between two quantities with respect to the percentage change in the price of one good—in the context of household food production. Chapter 3 estimates the elasticity of export quantity and value with respect to delays in the time it takes to load or unload products at US ports. Chapter 1 estimates the price elasticities in agricultural trade. Armington elasticities, the elasticity of substitution between goods from different countries, are key parameters in agricultural trade policy evaluation and welfare calculation. We estimate Armington elasticities for a selected basket of 38 agricultural commodities in 5 categories by compiling a sample of 118 countries' production and trade flows. Following and extending Feenstra et al. (2018), we estimate both the micro-elasticity of substitution between foreign sources of imports and the macro-elasticity of substitution between home and imported products at the commodity level. The median of the micro- and macro-elasticities are 6.4 and 5.0, respectively. Meat products have the lowest micro- and macro-elasticities, with the micro-elasticities ranging from 4.2 (pork) to 5.0 (poultry) and the macro-elasticities ranging from 2.9 (pork) to 4.5 (beef). Crops products have the widest range of Armington elasticities, with micro-elasticities ranging from 2.5 (pigeon peas) to 90.3 (peanuts), and macro-elasticities ranging from 1.2 (pigeon peas) to 20.1 (peanuts). In line with the literature, we find that 75 percent of the agricultural commodities have numerically smaller macro-elasticities than micro-elasticities, even though only 6 of them (pork, poultry, corn, peanuts, apples, and peppers) are statistically smaller at the 5 percent level. We explore the robustness of our estimates by slicing the sample into separate periods and importing countries. Finally, we discuss the policy implications of our estimates on predicting trade due to tariff changes and understanding welfare gains from agricultural trade. Chapter 2 estimates the goods-time elasticity of substitution (EOS), the responsiveness of the difference between money and time in household production for change of opportunity cost of time (OCT). This chapter bridges the gap between literature that directly and indirectly estimates the goods-time EOS in household production. Inspired by the studies in environmental economics, we argue the opportunity cost of time in household production not only depends on wage but life-cycle dynamics and household demographics as well. We proceed with the estimation by two strategies: direct estimation of the household production, and the demand-supply approach borrowed from Feenstra's (1994) research on trade elasticities. Both strategies report the estimates are much larger than unit and closer to previous indirect estimates. We show our results are robust when applied to Aguiar and Hurst's (2007) sample, in which they employed the indirect estimation. The larger goods-time EOS indicates policies aiding households with money for groceries like the Supplemental Nutrition Assistance Program (SNAP) are more sufficient, since money for certain groceries can more easily substitute for time in making meals. Chapter 3 explores the elasticity of trade with respect to port congestion time. U.S. ports have struggled with significant supply chain congestion during the past two years. Anecdotal evidence shows the increasing port congestion brought substantial losses to U.S. exports, particularly agricultural shipments. However, previous studies are limited by the availability of explicit data on congestion times for unloading. This study first quantifies the association between port congestion days and U.S. agricultural exports, using monthly export data of top U.S. ports and their monthly average container and bulk shipments delays. We find one extra day delay of container shipments decreases U.S. agricultural monthly exports by 5 percent in quantity or 2 percent in value on average. That amounts to $63 million in monthly loss of export value on average, and Western U.S. ports are responsible for 69 percent of this total. The effect is most pronounced for the Western U.S. exports of bulk commodities, where congestion results in a 9 percent loss in quantity or 8 percent loss in value. For Eastern U.S., the most salient effect is on consumer commodities, with a loss of 3 percent in quantity and 3 percent in value. For the Gulf region, the largest effect is on bulk commodities, with a loss of 4 percent in quantity and 5 percent in value. The impacts of congestion on bulk shipments are both statistically and economically insignificant. However, we find some evidence that exporters substitute bulk cargoes with containers when bulk shipment delays at ports increase. The substitution of container shipments with bulk shipments, however, is unlikely. / Doctor of Philosophy / This dissertation explores price and time factors in trade and household production. All three chapters estimate the percentage change in a variable for the percentage change to some other variables (i.e., an elasticity). Chapter 1 estimates the elasticities in international agricultural trade. The core concept the first chapter relies on is the one-factor-one-price elasticity of substitution (OOES), or how the percentage change in the quantity of one good responds to the percentage change in the price (of itself or another good). Chapter 2 estimates the two-factor-one-price elasticity of substitution (TOES)—or the difference of percentage changes between two quantities with respect to the percentage change in the price of one good—in household food production context. The third chapter estimate the responsiveness of export quantity/value to time delays at port. The first chapter examines how the demand for agricultural product imports will respond to price change. The study quantifies the responsiveness at two levels—micro and macro—using the Armington model, in which the product from each country is considered as a "variety". The micro-level elasticities capture the import demand responsiveness for a country of variety, say, Australian beef, when beef import price from Australia changes; The macro-elasticities capture the import demand responsiveness when, say, beef import prices from all countries change. We estimate both elasticities for a basket of 38 commodities, to shed light on policies such as "trade war" and multilateral trade agreements. In the median, one percent increase in price from a country of variety decreases 6.4 percent of demand for it; one percent decrease of price from all countries increases import demand by 5.0 percent. The second chapter studies the substitutability between money and time in household production, or the goods-time elasticity of substitution (EOS), which captures the percentage change of money (for grocery purchases) relative to time (for food preparation and cleaning up, etc.) for the change of price of time. But what is the price of time in food production? Economists use the term opportunity cost of time (OCT), the highest value that household could spend their time on if not on food production. While most economists agree that OCT correlates with wage, this chapter argues the correlation differs by life cycle and household characteristics. What's more, OCT should also include non-wage factors like household characteristics. Maybe households with children in their middle age just value time with children more than the market wage. In this case, the value of time with children, instead of wage, could be their OCT in food production. Based on these arguments, the study estimates the goods-time EOS is much larger than in previous studies. The magnitude of goods-time EOS has strong policy implications for policies like the Supplemental Nutritional Assistance Program (SNAP), which provides lower-income households money to buy groceries. If money and time are more substitutable, SNAP benefits will be more sufficient since money for certain groceries can more easily substitute for time in making meals. If goods-time EOS is small, however, SNAP benefits will be less sufficient, since the groceries are hardly substitutable for time in food production, and households still need to input a significant amount of time. The third chapter considers the time factor in international trade. It leverages the bottleneck of the international supply chain, port delays, in past years to study the elasticity of trade with respect to port congestion time. The study focuses on U.S. agricultural exports of bulk shipments and container shipments. We estimate that each day of container shipment delay is associated with 5 percent decrease in export quantity and 2 percent decrease in export value. Compared with the estimates of micro-elasticities in Chapter 1, one-day delay of container shipment is equivalent to imposing extra 0.8 percent of tariff on U.S. agricultural products in the median. The effect of bulk shipment delay is muted. Chapter 3, combined with Chapter 1, sheds light on the price of time in agricultural trade.

We use the semi-inverse method to solve a St. Venant and an Almansi-Michell problem for a prismatic body made of a homogeneous and isotropic elastic material that is stress free in the reference configuration. In the St. Venant problem, only the end faces of the prismatic body are loaded by a set of self-equilibrated forces. In the Almansi-Michell problem self equilibrated surface tractions are also applied on the mantle of the body. The St. Venant problem is also analyzed for the following two cases: (i) the reference configuration is subjected to a hydrostatic pressure, and (ii) stress-strain relations contain terms that are quadratic in displacement gradients. The Signorini method is also used to analyze the St. Venant problem. Both for the St. Venant and the Almansi-Michell problems, the solution of the three dimensional problem is reduced to that of solving a sequence of two dimensional problems. For the St. Venant problem involving a second-order elastic material, the first order deformation is assumed to be an infinitesimal twist. In the solution of the Almansi-Michell problem, surface tractions on the mantle of the cylindrical body are expressed as a polynomial in the axial coordinate. When solving the problem by the semi-inverse method, displacements are also expressed as a polynomial in the axial coordinate. An explicit solution is obtained for a hollow circular cylindrical body with surface tractions on the mantle given by an affine function of the axial coordinate / Master of Science