The microstructure of the Sn-Ag-Cu solder is examined by optical microscopy and scanning electron microscopy (SEM) for various compositions near the ternary eutectic for different cooling rates from the solder melt. Focus is on the size and orientation of Sn grains as indicated by cross-polarized, light optical microscopy, and pole figures from x-ray diffraction. We find that both composition and cooling rate have strong influences on Sn grain size, with Sn grain size increasing an order of magnitude as Cu concentration increases from 0% to 1.1%. Cyclic growth twinning, with twinning angles near 60°, is observed in Sn-Ag-Cu alloys near the composition Sn-3.9Ag-0.6Cu.

The riser of a fluid catalytic cracking (FCC) unit cracks gas oil to make fuels such as gasoline and diesel. However, changes in quality, the nature of crude oil blends feedstocks, environmental changes, and the desire to obtain higher profitability lead to many alternative operating conditions of the FCC riser. The production objective of the riser is usually the maximization of gasoline and diesel. Here, an optimization framework is developed in gPROMS to maximize the gasoline in the riser of an industrial FCC unit (reported in the literature) while optimizing mass flow rates of catalyst and gas oil. A detailed mathematical model of the process developed is incorporated in the optimization framework. It was found that concurrent use of the optimal values of mass flow rates of catalyst (310.8 kg/s) and gas oil (44.8 kg/s) gives the lowest yield of gases, but when these optimum mass flow rates are used one at a time, they produced the same and better yield of gasoline (0.554 kg of lump/(kg of feed)).

Risk prediction scores are important tools to support clinical decision-making for patients with coronavirus disease (COVID-19). The objective of this paper was to validate the 4C mortality score, originally developed in the United Kingdom, for a Canadian population, and to examine its performance over time. We conducted an external validation study within a registry of COVID-19 positive hospital admissions in the Kitchener-Waterloo and Hamilton regions of southern Ontario between March 4, 2020 and June 13, 2021. We examined the validity of the 4C score to prognosticate in-hospital mortality using the area under the receiver operating characteristic curve (AUC) with 95% confidence intervals calculated via bootstrapping. The study included 959 individuals, of whom 224 (23.4%) died in-hospital. Median age was 72 years and 524 individuals (55%) were male. The AUC of the 4C score was 0.77, 95% confidence interval 0.79–0.87. Overall mortality rates across the pre-defined risk groups were 0% (Low), 8.0% (Intermediate), 27.2% (High), and 54.2% (Very High). Wave 1, 2 and 3 values of the AUC were 0.81 (0.76, 0.86), 0.74 (0.69, 0.80), and 0.76 (0.69, 0.83) respectively. The 4C score is a valid tool to prognosticate mortality from COVID-19 in Canadian hospitals and can be used to prioritize care and resources for patients at greatest risk of death.

In this work a simulation of detailed steady state model of an industrial fluid catalytic cracking (FCC) unit with a newly proposed six-lumped kinetic model which cracks gas oil into diesel, gasoline, liquefied petroleum gas (LPG), dry gas and coke. Frequency factors, activation energies and heats of reaction for the catalytic cracking kinetics and a number of model parameters were estimated using a model based parameter estimation technique along with data from an industrial FCC unit in Sudan. The estimated parameters were used to predict the major riser fractions; diesel as 0.1842 kg-lump/kg-feed with a 0.81% error while gasoline as 0.4863 kg-lump/kg-feed with a 2.71% error compared with the plant data. Thus, with good confidence, the developed kinetic model is able to simulate any type of FCC riser with six-lump model as catalyst-to-oil (C/O) ratios were varied and the results predicted the typical riser profiles.