Connections and Divisions in On Certainty

The central claim of this paper is that On Certainty (1969)\ud is not to be seen as a "work� of Wittgenstein, but as an\ud assemblage from the enormous collection of material that\ud constitutes the Nachlass (cf. Stern 1996; Ackermann 1998;\ud Hintikka 1991). To substantiate this assertion, I will\ud critically compare the publication to its sources, namely\ud manuscripts 172, 174, 175, 176 and 177 of the Nachlass. I\ud will trace and value the decisions G.E.M. Anscombe and\ud G.H. von Wright have made in gathering this collection.\ud Their claim is twofold: first, Wittgenstein "marked it [On\ud Certainty] off in his notebooks as a separate topic�, and\ud second "it constitutes a single sustained treatment of the\ud topic� (Wittgenstein 1969, Preface). I will show that the first\ud claim is incorrect: not only are Wittgenstein"s "marks�\ud ambiguous, but the editors applied their own demarcations\ud in these notebooks as well. Their second claim is in need\ud of amplification. Wittgenstein"s concern with epistemological\ud issues is not limited to these five manuscripts: other\ud notebooks of the same period also contain entries that\ud strongly relate to topics discussed in On Certainty. I will\ud discuss examples from the undated notebooks MSS 169,\ud 170 and 171, published in Last Writings on the Philosophy\ud of Psychology, Vol. II: The "Inner� and the "Outer� (1992).\ud These show that it is difficult to make strict divisions in the\ud Nachlass in general, and in the late writings of the years\ud 1949-1951 in particular

The effect of the compatibilizer SEBS-g-GMA on the blend PP-PET: virgin and recycled materials

Abstract. In the carpet industry poly(ethylene terephthalate) (PET) and poly(propylene) (PP) are often used together within a single product. Mechanical recycling of these carpets results in a blend of PET and PP, which are immiscible. To enhance impact strength of this waste stream, the compatibilizer SEBS-g-GMA was used. More specific the transferability of earlier results with the compatibilizer, obtained on virgin PET-PP blends with amorphous PET (PETg), was assessed. Firstly, from these blends to blends with semi-crystalline PET (PETe) and secondly, from virgin to recycled materials. Two blends of virgin material were made containing 80 wt% PP and 20 wt% PETg or PETe. The effect of adding 2,5 wt% SEBS-g-GMA was assessed. Subsequently, post-industrial PP (r-PP) and post-consumer PETe (r-PETe) were blended and mechanical properties were measured for blends with and without compatibilizer. An increase in impact strength for the two virgin compatibilized blends (PP:PETg:SEBS-g-GMA and PP:PETe:SEBS-g-GMA) was expected and confirmed. A reduced effect of the compatibilizer on impact strength was observed for the recycled blends, due to the possible presence of contaminants. It was concluded that the results from virgin PETg-PP were directly transferable to virgin PETe-PP, but not entirely to recycled materials

In-Plane and Out-of-Plane Charge Dynamics of High-TcT_c Cuprates

We propose a theoretical expression for the $k$- and $\omega$-dependent dielectric function of a stack of two-dimensional layers coupled along the direction perpendicular to the layers, and discuss some of its properties. We argue that the plasma frequencies at $k=0$ should correspond to those which are experimentally obtained from optical measurements on {\em e.g.} La$_{1-x}$Sr$_{x}$CuO$_4$ via the $f$-sum rule analysis, regardless of the fact that such systems are strongly correlated. We discuss some of the ramifications due to strong anisotropy of the charge transport in these systems, and the lack of coherence for the transport in the direction perpendicular to the layers.Comment: 8 pages, postscript, uuencoded gz-compressed .tar fil