Development of adhesive test for hot-poured crack sealants

Sealants may be defined as the flexible materials used in cracks and/or joints preventing moisture infiltration into the pavements. These materials should acquire certain adhesive and cohesive properties to remain intact in the cracks and/or joints. Hot-poured applied crack sealants are one of the most common preventive techniques in North America that extend pavement life. However, most of these applied sealants fail due to their poor adhesion to crack walls. Various tests are currently used to measure the sealants’ adhesive properties. Most of these tests apply a mechanical load (tensile, shear, bending, torsion, and peeling) or study the chemistry at the interfaces, especially the molecular and interatomic forces generated at the interfaces. These tests, however, either lack a real correlation with field performance or have not yet been validated. This study introduces the development of a procedure for an adhesive prediction test, tensile adhesive method (TAM). It also evaluates the feasibility of two other tests: the single end notch interface (SENI) test and sessile drop method (SDM). TAM test, which is a modified version of the current crack sealant adhesion tester (CSAT) test, shows consistent results among specimens and users. In addition, it was successful in capturing the effect of temperature changes and aging effects. It is concluded that good adhesive properties of hot-poured crack sealant are required for desired field performance, which can be predicted from lab-aged specimen test results. However, other factors affecting sealant performance should be considered, including sealant installation, stiffness, and other preventive maintenance applied to the pavement

Concurring hypertrophic cardiomyopathy and takotsubo cardiomyopathy: Assessment and management

The prevalence of takotsubo cardiomyopathy (TCM) has been on the rise, but co-occurrence with hypertrophic cardiomyopathy (HOCM) remains rare. Although presenting patient demographics were similar to those in TCM, the potential for hemodynamic compromise was significantly compounded by the presence of underlying HOCM. Management was similar to standalone TCM, although use of inotropic agents and mechanical support appears to be more prevalent. Despite the increased potential for complications and the paucity of data regarding management, outcomes appear to be mostly favorable in both the hospitalization period and at follow-up. Interestingly, despite a new diagnosis of HOCM in about half the cases described, which signifies no significant left ventricular outflow tract (LVOT) gradient prior to TCM, half of those patients had a persistently elevated LVOT gradient after resolution of TCM. This poses a question of whether or not TCM can predispose to LVOT obstruction in HOCM patients even after its resolution

Development of Long-Term Aging Protocol for Implementation of the Illinois Flexibility Index Test (I-FIT)

The objective of this study was to evaluate long-term aging effects on asphalt mixtures using the Illinois Flexibility Index Test (I-FIT) and to develop a corresponding long-term aging protocol. The study recommended the use of the forced-draft oven as the aging equipment because of its availability, feasibility, practicability, capacity, and acceptable variability. A fully prepared semi-circular I-FIT specimen was chosen as the state of material during aging because it is practical, has limited operational variability, and its integrity is maintained during aging. The aging of compacted specimens for three days at 203°F (95°C) was found to be similar to aging for five days at 185°F (85°C) according to AASHTO R30, which is believed to be able to simulate up to 10 years of field aging. Hence, the 3D/95C aging method was chosen as the key component of the long-term aging protocol. Based on statistical analysis and oven-aging specimens immersed in argon, it was shown that the trends of aging after 1D/95C were similar to that observed after 3D/95C and 5D/85C. Hence, 1D/95C may be used as an indicator of 3D/95C aging for quality control purposes. Aging protocols were developed for laboratory-produced laboratory-compacted (LPLC) and plant-produced laboratory-compacted (PPLC) specimens. For LPLC, I-FIT on unaged and 3D/95C aged specimens should be conducted in all cases. A specific mix must have a mean flexibly index (FI) of unaged and 3D/95C aged specimens greater than 8.0 and 5.0, respectively, to be accepted. For PPLC, I-FIT procedure should be conducted on both unaged and 3D/95C aged specimens in all cases, while 1D/95C may be used by contractors to screen problematic mixes. Flexibility index higher than 8.0 and 4.0 for unaged and 3D/95C aged specimens, respectively, must be satisfied.IDOT-R27-175Ope

Numerical investigation of a fractional model of a tumor-immune surveillance via Caputo operator

Fractional calculus has become a potent tool for simulating the complexity of interactions in tumor-immune system dynamics. This paper investigates the existence and uniqueness of its approximation solutions of a fractional model of tumor-immune surveillance. This analysis is essential for proving the validity and dependability of the model and provides a more in-depth understanding of the dynamics of the tumor-immune surveillance system. Second, we examine the fractional model's numerical features. We utilize a numerical technique called the Laplace residual power series method to address the equations' complexity and nonlinearity. By defining the answers as a fractional power series, this method enables us to efficiently approximate the solutions. The use of this technique enables us to investigate the temporal evolution of the tumor-immune system, offering important insights into the stability and behavior of the system. We assess the effectiveness of the Laplace residual power series method in locating approximations through a series of thorough numerical simulations. To ensure the correctness and dependability of our method, we compare the numerical findings whenever possible with well-known analytical solutions