MROS-68K,a memory resident operating system,for MC68000

The operating system described has been designed and implemented for use in dedicated one-purpose applications, typically in real tihe. Specific attention has been paid to flexible intertask contkol. In the first installation the application system was the steering and controlling of large hydraulic devices. Typical subtasks involved were measuring, coordinate transformations, control, teaching and following robotic paths and evaluating daily material transfkrs. As a programming effort, developing the operating system was fairly reasonable being of the order of three or four months for one person, including design, coding, testing and documentation.     

Bonded thick film SOI with pre-etched cavities

We have studied direct bonding and thinning of pre-etched silicon wafers. Silicon-on-insulator (SOI) substrates with pre-etched cavities provide freedom to MEMS design and enable manufacturing of advanced sensor structures (sensor structures that would be difficult or impossible with conventional substrates). Cavities with different shapes and sizes were etched on to the handle wafers. The etched handle wafers were bonded to unpatterned cap wafers in air or in vacuum. The bonding quality was evaluated with scanning acoustic microscopy and with HF-etching test. After bonding, the cap wafers were thinned down with grinding and polishing. The thickness variation of silicon diaphragm over the cavities was evaluated with cross-sectional SEM. The deflection of the Si film was measured with surface profilometry. To decrease the deflection and the thickness variation of the film, different support structures were placed inside the cavities.The bonding experiments carried out with patterned wafers showed that vacuum bonding results in slightly higher bonding energy than bonding in air. With large cavity fraction (80% of total wafer area), the air bonded samples had large void on the bonded interface. With smaller cavity fractions or with vacuum bonded samples, no such voids were found. Thinning studies showed that the thickness variation of the silicon diaphragm increases with increasing cavity dimensions and with decreasing SOI layer thickness. Thickness variation can be reduced with support structures under the Si membrane.     

Additive influence on wear and friction performance of environmentally adapted lubricants

In this paper, the influence of concentration level and chemical composition of three different additive types on friction and wear coefficient are presented for a synthetic ester base fluid and a mineral base oil. One extreme-pressure (EP), two antiwear (AW) and two yellow metal passivator (Cu-passivators) additives were used. Factorial experimental design was used as the basis for a systematic evaluation of wear rates under mixed and boundary lubrication conditions. A total of 33 different lubricant blends were tested in a Plint and Partner High Frequency Friction Machine. For the synthetic ester, the extreme-pressure (EP) additive, containing phosphorus and nitrogen, was found to be much more effective in reducing wear than either of the two antiwear (AW) additives tested. In fact, the AW and Cu-passivator additives made little or no contribution to the wear protection in most of the cases studied. A synergy effect between the three additive combinations was observed only for the reference mineral oil blend. A significant difference between the antiwear performance of the test lubricants was found. This study suggests that the traditional “AW” and “EP” labels associated with commonly used additives are poor aids when designing of ester based lubricants.     

Extensions of MSO and the monadic counting hierarchy

In this paper, we study the expressive power of the extension of first-order logic by the unary second-order majority quantifier Most¹. In 1 it was shown that the extension of FO by second-order majority quantifiers of all arities describes exactly the problems in the counting hierarchy. We consider first certain sublogics of FO(Most¹) over unary vocabularies. We show that over unary vocabularies the logic MSO(R), where MSO is monadic second-order logic and R is the first-order Rescher quantifier, can be characterized by Presburger arithmetic, whereas the logic MSO(Rⁿ)_n∈Z+, where Rⁿ is the nth vectorization of R, corresponds to the Δ₀-fragment of arithmetic. Then we show that FO(Most¹)?MSO(Rⁿ)_n∈Z+ and that, on unary vocabularies, FO(Most¹) collapses to uniform-TC⁰. Using this collapse, we show that first-order logic with the binary second-order majority quantifier is strictly more expressive than FO(Most¹) over the empty vocabulary. On the other hand, over strings, FO(Most¹) is shown to capture the linear fragment of the counting hierarchy. Finally we show that, over non-unary vocabularies, FO(Most¹) can express problems complete via first-order reductions for each level of the counting hierarchy.     

Nonlinear optimization of steel production using traditional and novel blast furnace operation strategies

The high energy requirements in primary steelmaking make this industrial sector a major contributor to the global emissions of carbon dioxide. Ways to suppress the use of fossil reductants and the emissions from the processes should therefore be developed. The present work applies simulation and optimization for studying the economic feasibility of recycling blast furnace top gas to the combustion zones after CO₂ stripping. The study comprises the unit processes in an integrated steel plant, paying special attention to the blast furnace and the preheating of the blast or the recycled top gas. The system is optimized with nonlinear programming with respect to some central variables under different CO₂ sequestration and emission costs, which yields information about the economic feasibility of the concept. It is demonstrated that the optimal states of the plant show complex transitions, where the costs play a decisive role. It is also shown that hot gas recycling with CO₂ capture and storage would dramatically reduce the harmful emissions from the process. The conditions under which top gas recycling is economically feasible are also reported, as well as the effect of omitting oil injection in a blast furnace with top gas recycling.