Generation of volatiles by thermal treatments has been studied in saffron spice for two reasons: (a) to determine volatile profile changes during simulated aging processes and (b) to study the volatile generation pathway. During the aging process, while the amounts of C10 compounds such as safranal and HTCC increase, the amounts of C9 compounds such as isophorone and 2,6,6-trimethylcyclohexane-...

Exposure to extended periods of sub-Tg temperatures causes physical changes in the molecular structure of epoxy resins and epoxy-based materials to occur. These physical aging mechanisms include the reduction in free volume and changes to the molecular configuration. As a result, mechanical, thermodynamic, and physical properties are affected in ways that can compromise the reliability of epoxy...

Soft solids with tunable mechanical response are at the core of new material technologies, but a crucial limit for applications is their progressive aging over time, which dramatically affects their functionalities. The generally accepted paradigm is that such aging is gradual and its origin is in slower than exponential microscopic dynamics, akin to the ones in supercooled liquids or glasses. ...

Non-reversing relaxation enthalpies (∆H nr) at glass transitions T g (x) in the P x Ge x Se 1-2x ternary display a wide, sharp and deep global minimum (~0) in the 0.09 < x < 0.145 range, within which T g becomes thermally reversing. In the reversibility window these glasses are found not to age, in contrast to aging observed for fragile glass compositions outside the window. Thermal reversibili...

OBJECTIVES This in vitro study tested the influence of diverse stress simulation parameters on the fracture strength of all-ceramic three-unit fixed partial dentures (FPDs). METHODS All-ceramic FPDs made of Empress 2 (Ivoclar-Vivadent, FL) were exposed to thermal cycling and mechanical loading (TCML) with varying loading parameters such as chewing force (amount, frequency), thermal loading, l...

Industrial ventilation problems can be linked to the formation of thermal plumes that develop due to natural convection above various heat sources. These plumes, independent of the energy losses and thermal constraints caused, can also be the carrier of polluting products. This article describes an experimental study of the dynamic, thermal, and mass fields that develop from a hot rectangular (...

Objective To evaluate the influence of artificial aging on transformation propagation and fracture resistance zirconia implants. Methods One-piece (with integrated implant abutment, 1P; regular diameter [4.1mm]; n = 16) two-piece separate 2P; wide [5 mm]; implants were embedded according to ISO 14801. A titanium–zirconium (Ti-Zr; 4.1 mm diameter) served as a control (n 16). One subgroup 8) each...

It has been hypothesized that cellular damage caused by oxidative stress is associated with late-life depression but epidemiological evidence is limited. In the present study we evaluated the association between urinary 8-iso-prostaglandin F2α (8-iso-PGF2α), a biomarker of lipid peroxidation, and depressed mood in a large sample of community-dwelling older adults. Participants were selected fro...

This paper investigates the impact of isothermal aging on the long-term reliability of lead-free solder joints. The full experimental matrix contains SAC105 and SAC305 solder alloys assembled in ball grid arrays (BGAs) with package sizes ranging from 19mm, 0.8mm pitch to 5mm, 0.4mm pitch, and three surface platings (ImAg, ENIG, and ENEPIG). The test specimens were subjected to isothermal aging ...

Past works showed that the degradation of the passive devices caused by aging could induce failures of electronic system, including a harmful evolution of electromagnetic compatibility. This paper presents the impact of accelerated aging conditions on several typical passive components (capacitor, inductor). The preliminary degradation models of electrolytic capacitor and powder iron inductor a...