Obtaining Calcium Sulfoaluminate Using Aluminate Waste

In this work, studies have been carried out to replace bauxite with aluminate slags. Compounds of raw mixtures without use of fossil aluminate materials with different gypsum content have been developed. Instability of assimilation of anhydrite into calcium sulphoaluminate has been established. X-ray phase analysis has shown a weak dependence of increase in the firing temperature and increase in the yield of the main mineral C3A3·CŜ. Results of the study allow us to conclude that it is possible to obtain high-quality calcium sulphoaluminate (SAC) based on technogenic aluminate raw material.

Measurement-based evaluation of Google/Apple Exposure Notification API for proximity detection in a commuter bus

We report on the results of a measurement study carried out on a commuter bus in Dublin, Ireland using the Google/Apple Exposure Notification (GAEN) API. This API is likely to be widely used by Covid-19 contact tracing apps. Measurements were collected between 60 pairs of Android handset locations and are publicly available. We find that the attenuation level reported by the GAEN API need not increase with distance between handsets, consistent with there being a complex radio environment inside a bus caused by the metal-rich environment. Changing the people sitting in a pair of seats can cause variations of ±10dB in the attenuation level reported by the GAEN API. Applying the rule used by the Swiss Covid-19 contact tracing app to trigger an exposure notification to our bus measurements we find that no exposure notifications would have been triggered despite the fact that all pairs of handsets were within 2m of one another for at least 15 mins. Applying an alternative threshold-based exposure notification rule can somewhat improve performance to a detection rate of 5% when an exposure duration threshold of 15 minutes is used, increasing to 8% when the exposure duration threshold is reduced to 10 mins. Stratifying the data by distance between pairs of handsets indicates that there is only a weak dependence of detection rate on distance.

Financial Literacy

The present paper explores various approaches to the development of cognitive process dimensions in financial literacy. Applying the regression model, the study has examined the strength of the relationship between the actual financial competence of 413 Brazilian’s students aged 18-21, studying economic disciplines, and their school performance. The research has produced the following conclusions: (a) a weak dependence of actual skills on school performance; (b) inherently associated consequence of school performance is not corresponding to the actual financial skills; (c) a low level of financial competence in the dimensions - Remember, Understand and Apply.

Weak Dependence Notions and Their Mutual Relationships

New weak notions of positive dependence between the components X and Y of a random pair (X,Y) have been considered in recent papers that deal with the effects of dependence on conditional residual lifetimes and conditional inactivity times. The purpose of this paper is to provide a structured framework for the definition and description of these notions, and other new ones, and to describe their mutual relationships. An exhaustive review of some well-know notions of dependence, with a complete description of the equivalent definitions and reciprocal relationships, some of them expressed in terms of the properties of the copula or survival copula of (X,Y), is also provided.