Toward a theory of infiltration in a medium with dual porosity

A study is made of the filling, with a fluid, of a model medium consisting of two interacting continua whose interpenetrating pore spaces are formed of pores that are roughly identical within the confines of the respective continua.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 56, No. 6, pp. 953–960, June, 1989.     

Fatalities caused by nonvenomous animals: a ten-year summary from Sweden

All 58 deaths caused by nonvenomous animals in Sweden 1975-1984 were scrutinized. In 38 cases horses were involved, in 16 cattle and in one case each a moose, a lion, a dog and a ram. In the horse-related fatalities, the most common cause of accident was that the horse bolted or reared, causing the rider to fall off the horse or the cart or sulky. Falls were thus associated with 22 horse-related deaths. In cattle-related accidents, all fatalities where the cause of accident was known occurred due to aggressive behaviour of the animal. In horse-related accidents, head injuries dominated, while in cattle-related accidents head and chest injuries were equally common. It is suggested that wearing a proper helmet is the most important safety measure in horse-related activities. In cattle-related activities, the herding of untethered bulls together with cows is particularly dangerous and should be avoided.     

A Taxonomy of QoS-Aware, Adaptive Event-Dissemination Middleware

Event broker networks - scalable versions of the publish-subscribe paradigm - act as peer-to-peer overlays on broker nodes. Various frameworks support different overlay topologies and routing schemes for event dissemination, but attention is now turning to the nonfunctional attributes (such as quality of service) of such systems. Although many research efforts are starting to address the need for adaptation and QoS, no taxonomies or comprehensive surveys of adaptive middleware, which provide support for service guarantees, exist yet. To tackle this knowledge gap, the authors examine existing event-based middleware efforts, focusing on quality of service and adaptation.     

Nahalal: Cache Organization for Chip Multiprocessors

This paper addresses cache organization in chip multiprocessors (CMPs). We show that in CMP systems it is valuable to distinguish between shared data, which is accessed by multiple cores, and private data accessed by a single core. We introduce Nahalal, an architecture whose novel floorplan topology partitions cached data according to its usage (shared versus private data), and thus enables fast access to shared data for all processors while preserving the vicinity of private data to each processor. Nahalal exhibits significant improvements in cache access latency compared to a traditional cache design.     

An optimistic locking technique for concurrency control indistributed databases

A method called optimistic method with dummy locks (ODL) is suggested for concurrency control in distributed databases. It is shown that by using long-term dummy locks, the need for the information about the write sets of validated transactions is eliminated and, during the validation test, only the related sites are checked. The transactions to be aborted are immediately recognized before the validation test, reducing the costs of restarts. Usual read and write locks are used as short-term locks during the validation test. The use of short-term locks in the optimistic approach eliminates the need for the system-wide critical section and results in a distributed and parallel validation test. The performance of ODL is compared with strict two-phase locking (2PL) through simulation, and it is found out that for the low conflict cases they perform almost the same, but for the high conflicting cases, ODL performs better than strict 2PL     

Defect structure of acceptor-doped calcium titanate at elevated temperatures

The defect structure of acceptor (Al or Cr)-doped polycrystalline calcium titanate was investigated by measuring the oxygen partial pressure dependence (at 10° to 10–18 atm) of the electrical conductivity at 1000 and 1050° C. The observed electrical conductivity data were proportional to for the oxygen pressure range < 10^–10 atm and proportional to for the oxygen pressure range ( 10^–7 atm. The conductivity values were observed to increase with the acceptor concentration in the p-type region with the shift in the conductivity minima towards lower oxygen partial pressure. The absolute value of the electrical conductivity in the acceptor-doped samples were lower in the n-type region compared to the values in the undoped CaTiO₃. Aluminium and chromium were found to be equally effective in acting as acceptor impurities in CaTiO₃. The defect chemistry of CaTiO₃ is dominated by the added acceptor impurities for the entire oxygen partial pressure range used in this investigation.     

New inorganic proton conductors

High values of proton conductivity have been observed in a class of hydrated metal oxide pyrochlores, HMO₃·xH₂O (M = Sb, Nb, Ta). Two new polymorphs of HSbO₃·xH₂O have been synthesized and are also found to be good proton conductors. One polymorph has a layer structure and is derived from KSbO₃ with the ilmenite structure. The other new HSbO₃·xH₂O polymorph has the cubic KSbO₃ structure. A correlation of TGA, IR, NMR, and proton conductivity data suggests that the best inorganic proton conductors (10^?2 (Ωcm)^?1 at 80°C) are hydrates; this supports a Grotthus-type conduction mechanism analogous to that observed in aqueous media.     

Steady-state photoresponse theory for transition-metal-doped semiconductor photoanodes in aqueous electrolytes

The effect of the dopant ions on the steady-state photoresponse of transition-metal-doped semiconductor electrodes in aqueous electrolytes is examined with particular attention to minority carrier lifetime and transport characteristics. An approximate treatment is introduced which takes into account the variation in hole lifetime with position in the depletion region and the effect of the impurity centers on the effective hole mobility. The results obtained clearly resemble the known photocurrent-voltage characteristics of a number of such systems.     

On the investigation of d.c. plasmatron discharges by optical emission spectrometry

We investigated the emission spectra resulting from high rate plasmatron sputtering in order to gain further information on the coating process. The measured relations between the peak intensities of the target material and such plasmatron discharge parameters as discharge current, discharge power and deposition rate were almost linear. However, the intensity showed a strong pressure dependence. In the case of reactive high rate sputtering there is a drastic drop in the spectral line intensity of the target material as the pressure of the reaction gas increases. The behaviour of both the line intensity and the discharge voltage clearly reflects the coverage of the target with reaction products as a function of the pressure ratio p_O2/p_tot. The effects of the residual gas on the metal sputter rate and the desorption of H₂O during r.f. substrate cleaning were verified. From these results it is seen that emission spectroscopy may be used to advantage for monitoring the process of high rate plasmatron sputtering.