A Universal Continuum of Weight aleph

We prove that every continuum of weight aleph_1 is a continuous image of the Cech-Stone-remainder R^* of the real line. It follows that under CH the remainder of the half line [0,infty) is universal among the continua of weight c --- universal in the `mapping onto' sense. We complement this result by showing that 1) under MA every continuum of weight less than c is a continuous image of R^* 2) in the Cohen model the long segment of length omega_2+1 is not a continuous image of R^*, and 3) PFA implies that I_u is not a continuous image of R^*, whenever u is a c-saturated ultrafilter. We also show that a universal continuum can be gotten from a c-saturated ultrafilter on omega and that it is consistent that there is no universal continuum of weight c.Comment: 15 pages; 1999-01-27: revision, following referee's report; improved presentation some additional results; 2000-01-24: final version, to appear in Trans. Amer. Math. So

A separable non-remainder of H

We prove that there is a compact separable continuum that (consistently) is not a remainder of the real line.Comment: Rewrite after referee's comment

The measure algebra does not always embed

The Open Colouring Axiom implies that the measure algebra cannot be embedded into P(N)/fin. We also discuss the errors in previous results on the embeddability of the measure algebra.Comment: 10 pages 2000/01/24: final version, 11 page

Comparative thermal performance test for GGBS and OPC concrete mixes

The research investigates the effect of heating two concrete types and profiles to evaluate the most effective material during diurnal heating and cooling cycles. Plain and finned concrete slabs were manufactured from concrete with a 100% - PC binder (CEM 1) and a binder using 50% - PC and 50% GGBS (CEM 111). The slabs were subject to mainly radiative heat for a 7.5 hour daytime period and left to cool for 16.5 hours. Comparative readings were taken to measure the temperature difference between the two types of concrete during heating and cooling. The findings showed concrete manufactured with GGBS had a lower heat build up and release when compared to concrete manufactured with 100% CEM 1 binder. The research was limited to one comparative test at a single concrete strength with a single water cement ratio, and 50% GGBS cement replacement. Various GGBS cement replacement percentages could be tried to evaluate heat build up and release. Further research on U and Y values are also worthy of further investigation. Thermal mass could be improved thus reducing the need to use energy intensive air conditioning systems