Studies of Nucleation Phase of Mn-doped Cadmium-Selenide (CdSe) Quantum Dots Via Photoluminescence Spectroscopy

In this paper, we predict the nucleation phase of as-synthesized manganese (Mn) doped cadmium selenide (CdSe) quantum dots (QDs) at an intrinsic physical size of 3 (± 0.1 – 0.9) nm via photoluminescence (PL) studies. The nucleation phase was analyzed at temporal evolution (16, 46 and 90 mins) and temperature (210, 215 and 220 ºC) below the CdSe QDs reaction temperature (210 and 215 ºC) to it reaction temperature (220 ºC). The PL spectra`s observed to be against the QDs ripening behaviour of QDs since there are no prominent red-shift of PL spectra`s. However, the intensity of PL spectra`s shows to be varied with different temperatures and times.

Size Evolution and Composition of the Intermediate Phase During Nonclassical Protein Crystal Growth from Solution

<div>We propose here that the intermediate nucleation phase identified in a certain case</div><div>of protein crystal growth actually consists of two distinct parts; a low density and</div><div>higher density phase. A theory for crystal growth is utilized to study the formation</div><div>and growth of each phase. Within the framework of this theory the low density phase</div><div>is shown to obey a forth order kinetic law while the high density phase is zeroth order.</div><div>The combination of these two phases is shown to be a good match for X-ray diffraction </div><div>data which is indicative of its presence. The crystal growth rate is then given</div><div>in terms of the kinetic behavior of the intermediate nucleation phase. From this, the</div><div>crystal radius is estimated and shown to compare favorably with reported size data.</div><div>A method is proposed for determining the conditions that lead to protein crystals of</div><div>largest possible size.</div>

Size Evolution and Composition of the Intermediate Phase During Nonclassical Protein Crystal Growth from Solution

<div>We propose here that the intermediate nucleation phase identified in a certain case</div><div>of protein crystal growth actually consists of two distinct parts; a low density and</div><div>higher density phase. A theory for crystal growth is utilized to study the formation</div><div>and growth of each phase. Within the framework of this theory the low density phase</div><div>is shown to obey a forth order kinetic law while the high density phase is zeroth order.</div><div>The combination of these two phases is shown to be a good match for X-ray diffraction </div><div>data which is indicative of its presence. The crystal growth rate is then given</div><div>in terms of the kinetic behavior of the intermediate nucleation phase. From this, the</div><div>crystal radius is estimated and shown to compare favorably with reported size data.</div><div>A method is proposed for determining the conditions that lead to protein crystals of</div><div>largest possible size.</div>

Probabilistic Fracture Mechanics Framework Including Crack Nucleation of Rotor Forging Flaws

We present a probabilistic rotor life prediction framework that combines the forging flaw crack nucleation process and the subsequent crack growth to failure. Experimental fatigue tests of specimens including forging flaws show that the life cycle of a forging flaw can be described by a nucleation phase followed by a fatigue crack growth phase. These results demonstrate that the nucleation phase is a significant fraction of the whole life cycle to failure. However, as there is no engineering method available that describes reliably the nucleation phase, this portion is oftentimes neglected in engineering life prediction frameworks, therefore resulting in a conservative life quantification. In order to improve probabilistic life quantification methods, we introduce a rigorous scheme that convolutes the local crack nucleation probabilities and the local crack growth failure probabilities in order to provide a local failure probability. Integration over the whole component then yields the total probability of failure for the engineering part under a specific load spectrum. A specific direct simulation Monte Carlo numerical implementation is demonstrated. It is applied to fatigue crack nucleation from large gas turbine rotor disk forging flaws followed by crack growth to component failure. For different regions of the analyzed rotor components, the results show the probabilistic interplay of the different temperature and stress dependences of the applied empirical nucleation models and the fatigue crack growth models. The presented probabilistic approach is generic and not restricted to the discussed fatigue nucleation and subsequent crack growth process in large rotor forgings. The framework can be applied to a variety of sequential failure processes including static and fatigue loading phenomena, as well as a multiplicity of failure modes and sequences relevant for engineering components.