Urbana University was a private university specializing in liberal arts education and located in Urbana, Ohio. In its final few years, it was purchased by Franklin University and was a branch campus of that university.
Experimental measurements of the stress–strain curve from uniaxial tension tests in hydrogen yielded both macroscopic hardening and softening results despite the fact that hydrogen increases the mobility of dislocations according to the hydrogen-enhanced localized plasticity (HELP) mechanism for embrittlement. In his seminal paper, Howard Birnbaum (Scripta Metallurgica et Materialia, 31(2), pp. 149–153, 1994) using dislocation plasticity explained the contradictory outcomes of the uniaxial tension test on the basis of the two fundamental principles of HELP, hydrogen-enhanced dislocation mobility, and hydrogen-induced plastic flow localization; principles whose effects have been experimentally observed in almost all metals and alloys. By way of example, Birnbaum showed that the flow stress increases in hydrogen if the increased dislocation mobility cannot balance the shear localization hardening effect. In this work, we revisit the dexterity of Birnbaum's theory from a continuum plasticity standpoint and develop a framework to calculate macroscopic flow stress versus plastic strain curves in the presence of plastic flow localization in hydrogen. We incorporate the hydrogen effect on the constitutive response of the material through its effect on the activation enthalpy and volume characterizing the motion of dislocations—parameters that can be measured experimentally. Then, on the basis of Birnbaum's theory, we demonstrate that the competing and combined hydrogen effects on enhanced localization and enhanced dislocation mobility can result in either macroscopic hardening or softening response depending on their individual intensity and magnitude.
This is the first report on the in vitro bioavailability of zinc (Zn) in silkworm ( Bombyx mori ) larva powder (SLP) developed for human consumption. We used the chick bioassay, which has been extensively employed to evaluate the relative Zn bioavailability of animal feeds and foodstuffs, using ZnSO 4 ⋅ H 2 O as the 100% reference standard. Multiple regression analysis of total tibia Zn against supplemental Zn intake yielded a slope-ratio relative bioavailability value of 175% for Zn in SLP, which was significantly higher ( ) than that of mulberry ( Morus alba ) leaf (91%). SLP is an excellent efficacious source of very highly bioavailable Zn.
The hygroscopic phase transition (HPT) latent heat of black carbon (BC) particles can affect the atmospheric energy budget. However, the source-dependent characteristics and underlying mechanisms remain poorly understood. Herein, three representative BCs (Corn Cob BC, Camphor Wood BC, and Coal BC) were systematically analyzed to quantify HPT latent heat and reveal component-specific contributions. By combining component-resolved analysis with differential scanning calorimetry, it was found that Coal BC exhibited the highest HPT latent heat at 97% RH (Delta H = 93.77 J g-1), which was approximately 253 times higher than that at 11% RH (Delta H = 0.37 J g-1). This was primarily driven by its inorganic component, including the water-extractable fraction (WEBC) and water-extractable minerals (WEM). The corresponding spectral shifts of WEBC (85-100 cm-1 blueshift) and WEM (100-105 cm-1 redshift) in O-H stretching bands under 97% RH indicate strong hydrogen-bonding and solvent effects. These inorganic-rich fractions, although accounting for only 10.1-18.0 wt % in Coal BC, controlled water uptake and latent-heat release, highlighting their pivotal role in BC's nonlinear thermodynamic behavior. This is the first study to quantitatively resolve BC's HPT latent heat and attribute it to specific components, providing thermodynamic insights for improving the parametrization of BC radiative effects in atmospheric models.
The emu is a short-day breeder and only the male exhibits egg incubation, during which there is an obligatory fast, suggesting a conflict between the motivations to reproduce and to feed. We studied reproductive and metabolic endocrinology during the circannual cycles in reproduction and body weight in males and females. Some males were allowed to incubate and, for others, incubation was prevented by egg removal. Females began to lose weight at the start of lay and total loss was related to clutch size. Length of lay and clutch size were strongly influenced by whether the male partner incubated. In males, testosterone concentrations were greatest around the winter solstice, declined immediately when incubation began, and remained low until seven weeks after incubation ended. Prolactin concentrations increased 5-fold greater during incubation, reflecting its role in incubation behaviour. Incubating males fasted, used up their body reserves, and rapidly recovered weight after incubation ended. Changes in body weight were related to changes in the circulating concentrations of thyroid hormones, insulin and glucagon. In conclusion, annual body weight cycles were determined largely by the demands of reproduction and, during the incubation fast, body reserves appear to be utilized in a highly regulated manner.
