Explicit finite volume modeling of aircraft anti-icing and de-icing

In this paper, a runback water and ice prediction model is extended to anti-icing and thermal de-icing situations. The resulting coupled equations that govern thin-film flow, ice accretion, and heat conduction in the multilayered system substrate-ice-water are solved using an explicit finite volume approach. The procedure is implemented in the three-dimensional icing code ICECREMO2, and both structured and unstructured grids can be considered. Numerical results are presented to compare the present code simulations to some data provided by other ice prediction codes and to show the capabilities of the present numerical tool.

Giovanni Battista Montano as Architectural Draughtsman: Recording the Past and Designing the Future

Giovanni Battista Montano (1534-1621), who was born in Milan and trained as a woodcarver, relocated permanently to Rome in the early 1570s where his interest in sculpting was replaced by intense study of the city’s antique monuments and ruins. Although Montano carried out several sculptural and architectural projects during his time in Rome, it is his surviving corpus of drawings that testifies to his passion of exploring ancient architecture through the medium of drawing. While Montano was not famous during his lifetime, a large body of his intriguing designs became celebrated and widely circulated after his death thanks to the 1624 publication of Montano’s designs by his loyal pupil, Giovanni Battista Soria. Montano’s lifelong work differs from virtually all of his predecessors and contemporaries in its “fantastical” and ornamental nature. This thesis explores Montano’s artistic training as it relates to his later interest in imaginatively reconstructing antique buildings, along with his disregard for archaeological or historical accuracy. The subject matter upon which Montano focused is discussed, along with his objective in creating a large corpus of half-historical, half-invented drawings. His drawing techniques are explored with specific reference to the largest group of extant Montano drawings, today housed in Sir John Soane’s Museum, London, England, and also in reference to three original Montano drawings in the Centre Canadien d’Architecture/Canadian Centre for Architecture, Montréal. Also explored is the legacy and impact of Montano’s drawings and the later publications of his designs on the works of Roman Baroque architects, specifically Borromini and Bernini. This thesis ultimately attempts to understand the impact of the intellectual and artistic environment surrounding Montano in late sixteenth and early seventeenth century Rome, his drawing techniques, his choice of subject matter, and the reception that his unique works received from contemporary artists and intellectuals, along with those of the following generation.

Ca2+- and volume-sensitive chloride currents are differentially regulated by agonists and store-operated Ca2+ entry.

Using patch-clamp and calcium imaging techniques, we characterized the effects of ATP and histamine on human keratinocytes. In the HaCaT cell line, both receptor agonists induced a transient elevation of [Ca2+]i in a Ca2+-free medium followed by a secondary [Ca2+]i rise upon Ca2+ readmission due to store-operated calcium entry (SOCE). In voltage-clamped cells, agonists activated two kinetically distinct currents, which showed differing voltage dependences and were identified as Ca2+-activated (ICl(Ca)) and volume-regulated (ICl, swell) chloride currents. NPPB and DIDS more efficiently inhibited ICl(Ca) and ICl, swell, respectively. Cell swelling caused by hypotonic solution invariably activated ICl, swell while regulatory volume decrease occurred in intact cells, as was found in flow cytometry experiments. The PLC inhibitor U-73122 blocked both agonist- and cell swelling–induced ICl, swell, while its inactive analogue U-73343 had no effect. ICl(Ca) could be activated by cytoplasmic calcium increase due to thapsigargin (TG)-induced SOCE as well as by buffering [Ca2+]i in the pipette solution at 500 nM. In contrast, ICl, swell could be directly activated by 1-oleoyl-2-acetyl-sn-glycerol (OAG), a cell-permeable DAG analogue, but neither by InsP3 infusion nor by the cytoplasmic calcium increase. PKC also had no role in its regulation. Agonists, OAG, and cell swelling induced ICl, swell in a nonadditive manner, suggesting their convergence on a common pathway. ICl, swell and ICl(Ca) showed only a limited overlap (i.e., simultaneous activation), although various maneuvers were able to induce these currents sequentially in the same cell. TG-induced SOCE strongly potentiated ICl(Ca), but abolished ICl, swell, thereby providing a clue for this paradox. Thus, we have established for the first time using a keratinocyte model that ICl, swell can be physiologically activated under isotonic conditions by receptors coupled to the phosphoinositide pathway. These results also suggest a novel function for SOCE, which can operate as a "selection" switch between closely localized channels.