Optimierung von Kohlenwasserstoffgelen aus analytisch definierbaren Komponenten 1. Mitteilung: Kohlenwasserstoffgele als Salbengrundlagen mit optimierten gewünschten Gebrauchseigenschaften

Optimization of Hydrocarbon Jellies from Analytically Definable Components, 1. Communication: Hydrocarbon Jellies as Ointment Bases with Optimized Desired Properties for Use The work being presented investigates various slack waxes, solid and liquid paraffines concerning to their suitability to improve hydrocarbon jellies. An important criterion for selecting the raw materials is the analytical evidence of their unchanging quality. As a result recipes are proposed for hydrocarbon jelly mixtures, blended from ozokerite, solid and liquid paraffines. By varying their proportions the hydrocarbon jellies are improved for different purposes e. g. an improved ductibility, or an improved drug-liberation.     

What Level of Mathematical Reasoning can Computer Science Demand of a Software Implementer?: Auf Deutsch: Welche Art mathematischer Argumentation darf die Informatikwissenschaft einem Softwareimplementierer auf jeden Fall zumuten?

The article starts out from the observation that software engineering splits in two large activity areas: Software specification with its verification and software implementation with its verification. To find answers to the question in the title the article studies a practical systems software engineering area where theory is better developed than compared to other areas: Compiler construction. Our answer is a conclusion from work in the DFG-project Verifix, U.Karlsruhe, U.Kiel, U.Ulm, 1995-2003. One very complex cooperational task has been construction of a so called initial correct compiler for a realistic high level programming (and compiler writing) language correctly implemented and executed on a real life host processor. The interface between compiling specification and compiler implementation is given by algebraic-style, conditional formula transformation or program term rewriting rules which the specifier figures out and must prove correct w. r. t. source program and target processor semantics and data and states representations.Intensive cooperation of compiling specifiers and compiler implementers has revealed that the implementer's mathematical reasoning is algebraic reasoning of moderate depth. The specifier overtakes semantical issues and does induction proofs, a field of much more intricate mathematical reasoning.     

On procedures as open subroutines. I

Summary An ALGOL program with open subroutines or macro program is a program whose procedures may be implemented as open subroutines. A macro program may be considered to be an abbreviated notation of a program without procedures. It is proved that the so called macro program problem is algorithmically unsolvable for ALGOL 60 and other ALGOL-like languages : There does not exist any algorithm which decides for any given program whether it is a macro program or not (Theorem 4.3 and 4.4 in part II). Sublanguages of ALGOL-like languages for which the macro program problem is solvable are furtheron investigated (Theorem 4.1, 5.2–5.5 in part II). For this purpose macro grammars theory is applied.The methods of the paper are developped in part I and the key lies in a generalized langugage ALGOL 60-P-G which has the so called modularity property : There is an effective process which constructs for every original ALGOL 60-P-G program a formally equivalent one without procedure nesting (Theorem 3.3). The process mainly works by eliminating global procedure parameters (Theorem 3.1). ALGOL 60 and other known ALGOL-like languages do not have the modularity property (Theorem 3.4). Elimination of global procedure parameters is successful only for sublanguages of ALGOL 60 (Theorem 2.3–2.7).     

Gelchromatographische Trennung von verzweigten Kohlenwasserstoffen aus Vaselinen 10. Mitteilung: Über den Einfluß chemischer und physikalischer Meßdaten auf die Gebrauchseigenschaften von Vaseline

Gel Chromatographic Separation of Branched Hydrocarbons from Vaselines 10: Influence of Chemical and Physical Data on the Practical Properties of Vaseline Six different iso-fractions from vaselines were examined for their chemical compositon. The vaseline samples were first fractionated into unsaturated hydrocarbons, n- and iso-paraffins using silver nitrate and urea-silicagel columns respectively. For the determination of chemical fine structure, the iso-fractions were fractionated according to molecular weights by preparative gel chromatography. The individual GPC-fractions were examined by IR-spectroscopy according to H. Luther and H. H. Oelert in order to determine the content of CH₂-groups in long and short chains, methyl groups, naphthenic CH₂-groups and tertiary C-atoms. Large differences between the structural groups were observed between the solid and liquid hydrocarbons within the same vaseline sample. The values found were used to postulate the hypothetical structural formulae.     

On an algorithm determining direct superclasses in Java and similar languages with inner classes—Its correctness,completeness and uniqueness of solutions

Some object oriented programming languages allow inner classes. All of them admit inheritance. This combination of inner classes and inheritance is very fruitful however less known. On the other hand it creates a serious problem: how to determine the direct superclass of a given class C, i.e. the class which class C directly inherits from. For there may be several classes of the same name in one program. A specification of the problem and a non-deterministic algorithm are provided. We prove that the algorithm is correct w.r.t. the specification and complete, i.e. if the algorithm signals an error then no solution exists. We show that the specification itself has at most one solution, in other words, it is a complete specification. This proves also that the corresponding parts of Java Language Specification are consistent and define uniquely a fragment of Java semantics.     

On termination problems for finitely interpreted ALGOL-like programs

Summary Main issue is: The actual termination problem for finitely interpreted non-deterministic ALGOL-like programs without procedure selfapplication and without global variables is algorithmically solvable. This result offers a new and substantial application of a theorem of Lipton: The above mentioned programs, restricted to deterministic ones, have a sound and relatively complete Hoare logic. So we conjecture: ALGOL-like programs (even non-deterministic ones with formal sharing of variables) without procedure selfapplication and without global variables have a sound and relatively complete Hoare deduction system with axioms and inference rules which reflect the syntactical structure of programs.     

Der Einfluß der chemischen Feinstruktur von Vaselinen auf physikalische und technologische Eigenschaften 12. Mitteilung: Über den Einfluß chemischer und physikalischer Meßdaten auf die Gebrauchseigenschaften von Vaseline

Influence of Chemical Fine Structure of Vaselines on Physical and Technological Properties, 12: Influence of Chemical and Physical Data on the Practical Properties of Vaseline The influence of iso-fractions apart from normal and unsaturated hydrocarbons on the tack property of vaselines was studied. The tack is found to be the sum of tacks contributed by various molecular weight fractions obtained by gel permeation chromatography, which correlate with the observed chemical structures. Furthermore, other expected correlations between chemical structural groups and physical data, such as slip point and viscosity, were confirmed, which enable exact characterization of the vaselines studied. The results show that two different compositions yield vaselines having good practical properties: a) composition consisting of a large amount of long chain branched low melting tacky high molecular weight hydrocarbons (C-30 to C-200) and small proportions of n-paraffins and liquid hydrocarbons; b) compositions consisting of little high molecular weight solid iso-hydrocarbons (C-20 to C-100) together with n-paraffins and a large proportion of viscous tacky oil, which is composed of molecules having many short side chains. Since the vaselines of the type b) liberate the incorporated drugs more easily than those of the type a), to which also the so called natural vaselines belong, the type b) vaselines are considered to be optimum compositions. Practical properties of polymer-free bases could be compared with polymer-containing original vaselines by quantitative separation of the high polymers. Improvement of the practical properties of vaselines containing large proportions of oil can be accomplished by the addition of polyethylenes having molecular weights around 20 000, which can be dissolved in the vaseline base at elevated temperatures, and, on cooling, they improve the gel structure; however, these additives have disadvantages from technological viewpoint, since the processing has to be done at room temperature. Polyisobutylenes, that are frequently used, are unsuitable for improvement of the structure.     

Klaus Samelsons frühe Beiträge zur Informatikentwicklung

Klaus Samelson, 1918 geboren und leider schon 1980 gestorben, leistete in den 1950/60er Jahren außerordentliche Pionierbeiträge zur Informatik, insbesondere zur Programmierung elektronischer Rechenanlagen und zur Entwicklung, Definition und Implementierung höherer Programmiersprachen.