Activity of Ni-Moly catalysts in tetralin or decalin dehydrogenation and in hydrogenation of coal-extract solution

The activity of several NiMoly catalysts in the processes of dehydrogenation of tetralin or decalin and hydrogenation of coal-extract solution has been determined. In both processes studied, the activities of the catalysts investigated have been found to follow rectilinear relations with quantity. It has also been shown that the activity of a NiMoly catalyst can be predicted in hydrogenation of coal-extract solution, from its activity in dehydrogenation of tetralin or decalin; the latter reaction is relatively simple to conduct in laboratory conditions. However, caution must be exercised when very narrow pores, making possible Knudsen diffusion of hydrogen at high pressure, exist in the catalyst.     

Ultraviolet surface plasmon-coupled emission using thin aluminum films

Surface plasmon-coupled emission (SPCE) is the directional radiation of light into a substrate due to excited fluorophores above a thin metal film. To date, SPCE has only been observed with visible wavelengths using silver or gold films. We now show that SPCE can be observed in the ultraviolet region of the spectrum using thin (20 nm) aluminum films. We observed directional emission in a quartz substrate from the DNA base analogue 2-aminopurine (2-AP). The SPCE radiation occurs within a narrow angle at 59 degrees from the normal to the hemicylindrical prism. The excitation conditions precluded the creation of surface plasmons by the incident light. The directional emission at 59 degrees is almost completely p-polarized, consistent with its origin from surface plasmons due to coupling of excited 2-AP with the aluminum. The emission spectra and lifetimes of the SPCE are those characteristic of 2-AP. Different emission wavelengths radiate at slightly different angles on the prism providing intrinsic spectral resolution from the aluminum film. These results indicate that SPCE can be used with numerous UV-absorbing fluorophores, suggesting biochemical applications with simultaneous surface plasmon resonance and SPCE binding assays.     

Waveguide-modulated surface plasmon-coupled emission of Nile blue in poly(vinyl alcohol) thin films

Surface plasmon-coupled emission (SPCE) phenomenon is the coupling of excited fluorophores near a silver film with surface plasmons, resulting in directional emission into the underlying glass substrates. We report a complex coupling of Nile Blue fluorophore with 50 nm silver mirror, resulting in emission at several angles in the glass substrate, with either s or p polarization. This complex pattern of directional and polarized emission appears to be due to optical waveguide effects occurring when the sample thickness becomes comparable to the emission wavelength. We expect waveguide-modulated SPCE to have applications to biophysics and sensing.     

Load-Balanced Location Management for Cellular Mobile Systems Using Quorums and Dynamic Hashing

This paper presents a new distributed location management strategy for cellular mobile systems. Its salient features are fast location update and query, load balancing among location servers, and scalability. The strategy employs dynamic hashing techniques and quorums to manage location update and query operations. The proposed strategy does not require a home location register (HLR) to be associated with each mobile node. Location updates and queries for a mobile node are multicast to subsets of location servers, which change with time depending on the location of mobile node/querying node and load on the servers. Simulation experiments demonstrate that such dynamism prevents situations of heavy load on some location servers when mobile nodes are not uniformly distributed in space, or when some mobile nodes have their location updated or queried more often than others. Also, queries return the latest location information of a mobile node with a very high probability. The proposed scheme requires at most one unicast and two rounds of message multicasting for location update and query operations. All multicast messages have a small payload and are restricted to the high bandwidth wired part of the mobile network resulting in low communication overhead. Moreover, if a quorum of location servers gets overloaded, part of its load can be transferred to another lightly loaded quorum using dynamic hashing techniques.     

Probleme und Lösungen beim Feuchtigkeitsschutz des Mauerwerks von Baudenkmälern am Beispiel zweier großer Barockbauten in Wrocław

Problems concerning damp‐proofing brick‐laid historic building – shown on the example of two huge baroque structures in Wrozław. Most brick‐laid historic buildings in Poland are in bad technological condition due to lack of proper damp and water insulations, hence they need immediate renovation. Water is the biggest enemy of building constructions, especially of historic structures. The main source of dampness in buildings is rainwater, ground capillary water and water present in humid air, absorbed by porous, hygroscopic materials. It is a difficult task to design and later effect the correct and efficient damp‐proofing, and requires specific interdisciplinary knowledge. The article describes some chosen problems that appeared in the course of designing and making damp insulations in two huge historic priceless baroque buildings situated near the Odra River in Wrocław, namely, the main building of the University of Wrocław and the building of National Ossolinski Institute in Wrocław.     

Variations in proximate composition and fatty acid profiles of Baltic sprat (Sprattus sprattus balticus)

The variability of the proximate composition and fatty acid profiles in samples of sprat (Sprattus sprattus balticus) from the southern Baltic Sea were studied in relation to the catch season and location, individual fish size, and sex. Fatty acid profiles depended on such features as fish size and lipid content, which depend on the season of the year in which the fish were caught. No differences in fatty acid profiles were noted between the sexes in the individuals examined. Studies on fish lipids are necessary as fish lipids are important in the prevention of cardiac disease. One of the chief advantages of fish lipids that is relevant to the prevention of cardiac disease is their n−3 to n−6 fatty acid ratio. The most advantageous ratio of these fatty acids was noted in sprat that were the smallest in length.     

TTL Prediction Schemes and the Effects of Inter-Update Time Distribution on Wireless Data Access

Modern mobile networks, such as GPRS and UMTS, support wireless data applications. One successful example is the ever popular i-Mode in Japan. Wireless data services (wireless Internet) become more important as more and more customers of handheld devices enjoy the convenience of the ubiquitous computing. To improve the effective wireless data access, the time-to-live (TTL) management for data entries becomes important due to its use in effective caching design. In this paper, we study three TTL prediction schemes and investigate the effects of the inter-update time distribution on the wireless data access. Performance analysis is carried out via simulations as well as analytical modeling. We expect our results will be useful for the future wireless data access systems, in which transmission power for mobile devices is more limited.     

Optimal Sequential Paging in Cellular Wireless Networks

In a high-capacity cellular network with limited spectral resources, it is desirable to minimize the radio bandwidth costs associated with paging when locating mobile users. Sequential paging, in which cells in the coverage area are partitioned into groups and paged in a non-increasing order of user location probabilities, permits a reduction in the average radio costs of paging at the expense of greater delay in locating the users. We present a polynomial time algorithm for minimizing paging cost under the average delay constraint, a problem that has previously been considered intractable. We show the conditions under which cluster paging, a simple heuristic technique proposed for use with dynamic location update schemes, is optimal. We also present analytical results on the average delay and paging cost obtained with sequential paging, including tight bounds.     

The role of interfacial energy in the wear of polymeric journal bearings

Experimental and theoretical relationships between the adhesional energy and the wear rate of a polymer, in the form of a miniature journal bearing for a steel shaft, are presented. Formulae are derived that can be used to predict the wear rate of a polymeric material in such bearings.     

Z-bunionectomy: retrospective long-term study

Long-term patient satisfaction and objective clinical and radiographic examinations of patients who had undergone the Z-bunionectomy at the University of Chicago Medical Center were evaluated. Fifty-six surgeries were performed on 31 patients, with a follow-up range of 5 to 9 years. The University of Maryland 100-Point Painful Foot Center Scoring System was modified to be more specific to bunion surgery, and we used this modification to measure patient satisfaction. Patient satisfaction was rated good to excellent by 90% of the patients. Radiographic findings included: intermetatarsal angle-mean, 7.1 degrees; hallux abductus angle-mean, 8.96 degrees; tibial sesamoid position-mean, 2.8. The mean protrusion was -1.64 mm. Radiographic findings consistent with osteonecrosis were noted of one patient, one foot, although the patient was clinically asymptomatic. The objective findings were as follows: dorsiflexion, mean, 60 degrees; plantarflexion, mean, 14 degrees. No patients had pain or crepitus, nor were they tract-bound in their first metatarsophalangeal joint range of motion. In addition, stance dorsiflexion had a mean of 21 degrees, and the purchase power was 88% good to excellent on plantar paper pull-out testing. First ray motion qualitatively demonstrated 1 1/2 to 2 times dorsiflexion to plantarflexion. There were no subsecond metatarsal head keratoses. Generalized ligamentous laxity was not seen. For the resting calcaneal stance position the mean was 3.5 degrees everted, with 24% of the patients maximally pronated in this position. We were unable to correlate any structural and functional postoperative features with patient satisfaction.