Concrete curing has long been realized to be important to produce durable concrete. Curing compound is widely used to cure concrete in the field. The current curing membrane evaluation method ASTM C 156, however, is incapable of distinguishing the curing compound quality and guiding the curing practice in the field. A new laboratory curing membrane evaluation protocol is developed in this study. It has the ability to rank the quality of curing compound and guide curing practice in the field according to the field ambient weather conditions and the type of curing compound. A series of field tests were conducted to investigate the key factors that affect the curing effectiveness in the field conditions. A finite element program, temperature and moisture analysis for curing concrete (TMAC2), is updated to solve the coupled and nonlinear heat transfer and moisture transport problems in early-age concrete. Moisture capacity is induced into the TMAC2, which makes it unique to characterize the self-desiccation. A full scale concrete pavement test study was conducted at the FAA National Airport Pavement Test Facility (NAPTF) near Atlantic City, New Jersey. In this study, the material properties, i.e. thermal conductivity and moisture diffusivity, were backcalculated from field data. Thereafter, backcalculated material properties were used to forward-calculate the temperature and moisture histories of all other sections. High order shear deformable theory is used to model the concrete slab curling and warping behavior because of highly nonlinear temperature and moisture gradients. The maximum shear strain is obtained a couple of inches below the concrete slab. This might account for the occurrence of delamination.

The Carrizo-Wilcox aquifer is a valuable groundwater resource, situated in a semi-arid landscape of Southwest Texas, where over-use by dependent farming practices has lowered aquifer levels. In semi-arid regions, rates of groundwater recharge are predominantly low due to high potential evapotranspiration rates; however, least understood is the role that vegetation plays in soil-plant-water dynamics. Vegetation management potentially plays a major role in countering the loss to recharge because evapotranspiration (ET) varies with vegetation type and cover. The conversion from shrubland to grassland likely reduces rooting depths and total plant cover. Subsequently, deep drainage (percolation below the root zone) will likely increase and lead to groundwater recharge, at least temporarily. The primary aims of the study were to identify those biotic and abiotic factors facilitating deep drainage and to examine differences in recharge for the years following clearing of natural shrub vegetation. Soil chloride was examined to estimate long-term recharge rates, since its concentration in the soil is influenced by the movement of water. Short-term soil moisture trends were also monitored for any water movement deep in the soil profile in response to individual rain events. Rooting depths decreased following removal of vegetation; yet root biomass unexpectedly increased due to successful grass establishment during the first five years after treatment. Soil properties did not vary between treatments, indicating that the majority of chloride differences seen were a consequence of vegetation change. Peak and total soil chloride concentrations were expected to decrease and occur deeper in the soil profile 15-30 years following the clearing of woody vegetation. Total chloride decreased by up to 65% after 30 years and resulted in an estimated 14.9 mm/yr more recharge compared to adjacent untreated controls. Evidence in this study suggest that much of this chloride is leached during the first five years following treatment and that more leaching occurs in especially wet periods. During the wet 2007 growing season, soil moisture below the root zone increased by up to 17% after vegetation clearing. The results of this study indicate that hydrologic changes following brush removal were evident in this system and are likely to positively influence groundwater recharge in the long-term.

The effect of moisture absorption on the glass transition temperature (Tg) and stress/strain behavior of network polyurethane shape memory polymer (SMP) foams has been investigated. With our ultimate goal of engineering polyurethane SMP foams for use in blood contacting environments, we have investigated the effects of moisture exposure on the physical properties of polyurethane foams. To our best knowledge, this study is the first to investigate the effects of moisture absorption at varying humidity levels (non-immersion and immersion) on the physical properties of polyurethane SMP foams. The SMP foams were exposed to differing humidity levels for varying lengths of time, and they exhibited a maximum water uptake of 8.0 percent (by mass) after exposure to 100 percent relative humidity for 96 h. Differential scanning calorimetry results demonstrated that water absorption significantly decreased the Tg of the foam, with a maximum water uptake shifting the Tg from 67 °C to 5 °C. Samples that were immersed in water for 96 h and immediately subjected to tensile testing exhibited 100 percent increases in failure strains and 500 percent decreases in failure stresses; however, in all cases of time and humidity exposure, the plasticization effect was reversible upon placing moisture-saturated samples in 40 percent humidity environments for 24 h.

This thesis analyzes the implementation of surface bonded piezoelectric actuators to control or minimize the deformation in elastic or viscoelastic cantilever beams due to simultaneous heat and moisture diffusion. The problem is addressed in the context of linearized elasticity and linearized viscoelasticity. The constitutive equations are derived from the balance laws for mass, linear and angular momenta, energy, entropy and the second law of thermodynamics. The constitutive equations for linearized elasticity are then obtained as a consequence of small deformation assumption. The temperature and moisture induced deformation is introduced through the coefficient of thermal expansion CTE and coefficient of moisture expansion CME. The constitutive equations for linearized viscoelasticity are obtained by correspondence principle. The coupled temperature and moisture diffusion equations are obtained as a consequence of Clausius-Duhem inequality. The extent of coupling between heat conduction and moisture diffusion phenomena is studied by varying the ratio of their diffusivities and a non-dimensional coupling parameter. The effect of coupled unsteady heat conduction and moisture diffusion phenomena on the short and long term response characteristics of the beam such as displacement, stress and strain fields is studied. Based on these response characteristics, the magnitude of external actuating voltage required to minimize deformation is predicted. This is followed by a comparative study of the field variables in cases of actuated and unactuated beams. Four materials are chosen for this study; aluminium, epoxy, carbon fiber reinforced polymer with fiber volume fraction of 60 percent, and an epoxy-like viscoelastic material. The viscoelastic material is assumed to be thermorheologically simple. The shift factor is assumed to be a linear function of temperature and moisture fields. To address this problem numerically, a finite difference formulation is presented for the field equations and boundary conditions. This numerical scheme is validated by solving the problem of uniformly loaded cantilever beam and comparing the results with the analytical solution known a priori. The results obtained numerically are validated by comparison with experimental results. It is observed that the under the effect of external actuation, the stress and displacement fields are largely minimized in all four cases chosen for study. The bending in the unactuated viscoelastic beam is more pronounced than bending in the unactuated elastic beam. This is due to the softening of the material with time due to evolving temperature and moisture fields. However, relatively lesser external actuating voltage is necessary to minimize bending in the former case compared to the latter. The magnitude of actuating electric field required in the piezoelectric layer suggests a need to address the problem with in a non-linear framework, no such attempt is made in this study.

To calculate the characteristics of electronic parts is divided by 1.Chip. 2.Assembly, i.e. package. 3. PCB (Printed Circuit Board). Analizing the electrical characteristics of package needs consideration from all system can distinguish the influence of function. Although the analysis method may be change but we can get the characteristics results from the parameters of circuit element (i.e. Resistance, Inductance, Capacitance). Different measurement or modeling technology can prove that the list data is correct. That moisture in plastic packages can cause cracking or delamination during the surface mount assembly process. During this process, the packages are heated to 220-240¢J. At these temperatures, any moisture present in the plastic vaporizes and exerts stresses in the package, which can cause delamination between the mold compound and the leadframe or die. The mismatch in thermal expansion coefficients of the package¡¦s components also induces stresses. If these combined stresses are greater than the fracture strength of the plastic, cracks will form. The susceptibility of a package to cracking depends on: 1.amount of absorbed moisture, 2.die size, 3.package design, 4.mold compound characteristics, 5.solder reflow temperature profile. Widely, flip chip technology is defined as mounting the chip to a substrate with any kind of materials and methods, as long as the chip surface (active area) is facing to the substrate. The advantages of FC-BGA is¡G1.Efficient use of PCB area. 2.Area array access for high I/O device. 3.Allow for finer pitches. 4.Fewer joints. 5.Better performance of high frequency application. 6.FC is and will be lowest cost.

The presence of moisture in hot mix asphalt (HMA) causes loss of strength and durability of the mix, which is referred to as moisture damage. This study deals with the development of experimental methods for measuring total suction in HMA, which can be defined as the free energy state of water in HMA mixes. The total suction is related to the ability of moisture to get into the mix under unsaturated conditions; it is also related to the ability of the mix to retain moisture. Soil suction has been studied extensively. However, suction in HMA as a porous material and its relationship to moisture damage have not been studied. The development of a procedure to measure the total suction in HMA mixes is the first objective of this research. The second objective is to relate suction measurements to physical and chemical properties of the mixtures. The objectives were achieved in two phases. In the first phase, the total suction was measured in HMA specimens with different types of aggregates (limestone and granite), and with different air void distributions and aggregate gradations. The results of this phase showed that the drying test using a 60 oC temperature-controlled room is the proper setup for measuring the total suction in HMA using thermocouple psychrometers. The characteristics of suction-moisture content curves were found to be related to the air void distribution in HMA. In the second phase, total suction was measured in sand asphalt specimens. These specimens had different combinations of aggregates and binders with different bond energies and exhibited different field performance in terms of resistance to moisture damage. The suction measurements in sand asphalt specimens were used to calculate the moisture diffusion coefficient. The results revealed that water diffused into sand asphalt specimens that are known to have poor resistance to moisture damage faster than those that are known to have good resistance to moisture damage

Thesis (doctoral)--Swiss Federal Institute of Technology, Zurich, 1997. / Vita. Includes bibliographical references (p. 121-128).

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 155-168). Available also in a digital version from Dissertation Abstracts.

Thesis (D.Phil.(Horticultural Science)--University of Pretoria, 2009. / Includes summary. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 121-134). Also available on the World Wide Web.