DSC investigations on condensation polymers—I. Analysis of the curing process

Curing reactions in thermosetting resins and resin-composite systems have been examined using differential scanning calorimetry. In particular, phenol-formaldehyde and melamine-formaldehyde systems have been investigated using small pressure-sealed capsules. Curing exotherms obtained from a single temperature scan have been analysed to give reaction kinetic parameters associated with the overall cure process. The reproducibility of the derived parameters, their variation with scan speed and the absolute values of reaction rate constants obtained, are discussed. The kinetic values are shown to be reasonably reliable when used to calculate extents of cure resulting from thermal curing cycles.     

Broadening and oscillator strengths of Cs quadrupole lines

The oscillator strengths of the first 14 quadrupole lines of $\text{Cs}\text{(6}{}^2\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{→5?11}{}^2\text{D}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext><mtext>,</mtext><mtext>3</mtext><mtext>2</mtext>}}\text{)}$ were measured in absorption using a high resolution spectrometer. In addition to this, the broadening of the$\text{6}{}^2\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{→5}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ and $\text{6}{}^2\text{S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{→5}{}^2\text{D}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ lines was investigated. Taking into account not only the impact region of the lines but also the quasi-static wings, the integrated absorption of the lines increases overproportionally to the practicle density. It was established that the electron transitions which form the quasi-static wings of the lines(molecular electron transitions) have higher transition probabilities than the corresponding impact broadened lines. A rough estimate of the molecular oscillator strengths is given.     

Über den Verband der Subnormalteiler einer endlichen,p-auflösbaren Gruppe

Ohne Zusammenfassung     

Graph Theory with Applications

Journal of the Operational Research Society -     

General decomposition theorems form-convex sets in the plane

A setS inR ^dis said to bem-convex,m≧2, if and only if for everym distinct points inS, at least one of the line segments determined by these points lies inS. Clearly any union ofm?1 convex sets ism-convex, yet the converse is false and has inspired some interesting mathematical questions: Under what conditions will anm-convex set be decomposable intom?1 convex sets? And for everym≧2, does there exist aσ(m) such that everym-convex set is a union ofσ(m) convex sets? Pathological examples convince the reader to restrict his attention to closed sets of dimension≦3, and this paper provides answers to the questions above for closed subsets of the plane. IfS is a closedm-convex set in the plane,m ≧ 2, the first question may be answered in one way by the following result: If there is some lineH supportingS at a pointp in the kernel ofS, thenS is a union ofm ? 1 convex sets. Using this result, it is possible to prove several decomposition theorems forS under varying conditions. Finally, an answer to the second question is given: Ifm≧3, thenS is a union of (m?1)³2 ^m?3 or fewer convex sets.