The role of paraffin wax in the formation of minor products in the catalytic cracking of petroleum distillates over La-Y

An investigation of the role of paraffin wax in the catalytic cracking of wax-bearing petroleum distillates has been carried out in a fixed-bed reactor containing La-Y catalyst over a temperature range from 482° to 524°C. By using the concept of initial product selectivity derived from the time-on-stream theory of catalyst decay, it was found that increasing the wax content of the feedstocks resulted in an increase in the yield of C₅⁺ gasoline and a decrease in the yields of most of the gaseous products and of coke. Ethane and propylene and the olefin content of the gasoline increased in yield with the addition of wax. The mixing of cracking feedstocks has only a linear effect on the reactivity and no synergistic effects in any of the observed properties of the reaction are in fact observed.     

Mixed self-assembled lipopolymers with spacer lipids enhancing sensitivity of lipid-derivative QCMs for odor sensors

An odor sensing system using a quartz crystal microbalance (QCM) sensor array and pattern recognition technique has been for years a main research topic in our group. For the general field of artificial olfaction using acoustic-wave based sensors such as QCMs it is vital to search for novel sensing materials. Here we present recent results of our ongoing study on application of pegylated lipids as coatings for QCM odor-sensors. The method presented herein is based on self-assembling of lipids and lipid-derivatives on the QCM surfaces. The disulphide-terminated lipids and lipopolymers are co-chemisorbed onto gold electrodes of QCM sensors by simple immersion in ethanolic solutions. This creates porous supports onto which additional layers of lipopolymers are physisorbed. The method allows for fabrication of lipopolymeric QCM odor-sensors with enhanced sensitivity to odorants, capable of very good discrimination among odorant samples—according to the functional group of an odorant.     

Mechanosynthesis of Nd-Fe-B alloys

A mechanical alloying technique has been applied for Nd-Fe-B alloy synthesis from the mixture of neodymium, iron and Fe-B powders. The direct formation of Nd₂Fe₁₄B phase ( phase) was not observed, but an Nd-Fe multilayer structure was formed during the milling process. Annealing of milled powders at 1023 K for 1 h resulted in magnet formation. The dependence of the magnetic properties on milling time was observed. For the applied milling device and parameters, the optimum milling time proved to be 4 h and the coercive force reached a value of about 1000 kAm^–1.     

Atomic RMI: A Distributed Transactional Memory Framework

This paper presents Atomic RMI, a distributed transactional memory framework that supports the control flow model of execution. Atomic RMI extends Java RMI with distributed transactions that can run on many Java virtual machines located on different network nodes. Our system employs SVA, a fully-pessimistic concurrency control algorithm that provides exclusive access to shared objects and supports rollback and fault tolerance. SVA is capable of achieving a relatively high level of parallelism by interweaving transactions that access the same objects and by making transactions that do not share objects independent of one another. It also allows any operations within transactions, including irrevocable ones, like system calls, and provides an unobtrusive API. Our evaluation shows that in most cases Atomic RMI performs better than fine grained mutual-exclusion and read/write locking mechanisms. Atomic RMI also performs better than an optimistic transactional memory in environments with high contention and a high ratio of write operations, while being competitive otherwise.     

Subatomic Natural Deduction for a Naturalistic First-Order Language with Non-Primitive Identity

A first-order language with a defined identity predicate is proposed whose apparatus for atomic predication is sensitive to grammatical categories of natural language (e.g., common nouns, verbs, adjectives, adverbs, modifiers). Subatomic natural deduction systems are defined for this naturalistic first-order language. These systems contain subatomic systems which govern the inferential relations which obtain between naturalistic atomic sentences and between their possibly composite components. As a main result it is shown that normal derivations in the defined systems enjoy the subexpression property which subsumes the subformula property with respect to atomic and identity formulae as a special case. The systems admit a proof-theoretic semantics which does not only apply to logically compound but also to atomic and identity formulae—as well as to their components. The potential of the defined systems for a meticulous first-order analysis of natural inferences whose validity crucially depends on expressions of some of the aforementioned categories is demonstrated.     

The COCA quality model for user documentation

According to Pedraz-Delhaes, users evaluate both the product and the vendor on the basis of provided documentation. Thus, a question arises as to what quality characteristics should be taken into account when making a decision about accepting a given user manual. There are some proposals (e.g., ISO Std. 26513 and 26514), but they contain too many quality characteristics and lack orthogonality. The goal of this paper is to propose a simple quality model for user documentation, along with acceptance methods based on it. The model is to be orthogonal and complete. As a result, the COCA quality model is presented, which comprises four orthogonal quality characteristics: Completeness, Operability, Correctness, and Appearance. To check completeness, the proposed quality model has been compared with many other quality models that are directly or indirectly concerned with user documentation. Moreover, two acceptance methods are described in the paper: pure review based on ISO Std. 1028:2008, and documentation evaluation test (a type of browser evaluation test), which is aimed at assessing the operability of user documentation. Initial quality profiles have been empirically collected for both methods—they can be used when interpreting evaluation results obtained for a given user manual.