Engineering Commons^™

Development Of Long-Term Aging Factor For Asphalt Mixtures’ Cracking Resistance, Yucheng Shi

LSU Master's Theses

To characterize the cracking resistance of asphalt mixtures, semi-circular bend (SCB) test has been developed and subsequently accepted as a routine test in mixture design in Louisiana. However, SCB test requires specimens to be aged for five days in laboratory, which makes it not implementable in quality control (QC)/quality assurance (QA).

The primary project objective was to develop an aging factor to transfer the unaged SCB Jc to the aged SCB Jc. Specific objectives were to: (1) investigate the effect of laboratory aging on asphalt mixtures’ cracking resistance and asphalt binders’ rheological and chemical properties, (2) develop an aging …

Understanding Asphalt Concrete Aging Using Nanoindentation, Hasan M. Faisal

Civil Engineering ETDs

Asphalt concrete (AC) is created by mixing liquid asphalt binder with solid aggregates. When asphalt binder is mixed with aggregates, it creates a thin film (about 7-16 microns thick) around the aggregate surface. Fine aggregate (smaller than 0.075 mm size) get entrapped within the binder film or mixed with the binder, and create a phase called mastic. Both asphalt film and mastic play significant roles in aging of asphalt pavement. To this day, tests were performed mainly on the bulk liquid asphalt, but not on the film or mastic. In this study, for the first time, nanoindentation tests were done …

Neuroimaging Biomarkers Of Mtor Inhibition On Vascular And Metabolic Functions In Aging Brain And Alzheimer’S Disease, Jennifer Lee, Lucille M. Yanckello, David Ma, Jared D. Hoffman, Ishita Parikh, Scott Thalman, Bjoern Bauer, Anika M. S. Hartz, Fahmeed Hyder, Ai-Ling Lin

Pharmacology and Nutritional Sciences Faculty Publications

The mechanistic target of rapamycin (mTOR) is a nutrient sensor of eukaryotic cells. Inhibition of mechanistic mTOR signaling can increase life and health span in various species via interventions that include rapamycin and caloric restriction (CR). In the central nervous system, mTOR inhibition demonstrates neuroprotective patterns in aging and Alzheimer’s disease (AD) by preserving mitochondrial function and reducing amyloid beta retention. However, the effects of mTOR inhibition for in vivo brain physiology remain largely unknown. Here, we review recent findings of in vivo metabolic and vascular measures using non-invasive, multimodal neuroimaging methods in rodent models for brain aging and AD. …

Artificial Gravity As A Countermeasure To The Cardiovascular Deconditioning Of Spaceflight: Gender Perspectives, Joyce M. Evans, Charles F. Knapp, Nandu Goswami

Biomedical Engineering Faculty Publications

Space flight-induced physiological deconditioning resulting from decreased gravitational input, decreased plasma volume, and disruption of regulatory mechanisms is a significant problem in returning astronauts as well as in normal aging. Here we review effects of a promising countermeasure on cardiovascular systems of healthy men and women undergoing Earth-based models of space-flight. This countermeasure is produced by a centrifuge and called artificial gravity (AG). Numerous studies have determined that AG improves orthostatic tolerance (as assessed by various protocols) of healthy ambulatory men, of men deconditioned by bed rest or by immersion (both wet and dry) and, in one case, following spaceflight. …