CONSAT: A parallel constraint satisfaction system

In this paper we describe the parallelization of a medium-size symbolic fixed-point computation, CONSAT. CONSAT is a constraint satisfaction system that computes globally consistent solutions. The parallel version of CONSAT is implemented using abstractions from a parallel programming toolbox we developed. The toolbox is intended for novice parallel programmers, and programs based on abstractions from this toolbox may be executed on both uniprocessors and shared-memory multiprocessors without modifications. We explain how parallelism is introduced, and how concurrent accesses to shared data structures are handled. We will also describe the performance of CONSAT on sample inputs.     

Vinyl composites—fiberglass reinforced PVC

Glass fiber reinforced PVC has several distinctive and useful properties. Its tensile strength can be twice that of unreinforced PVC. Excellent coupling of the glass fibers to the PVC matrix is required for good retention of tensile strength when exposed to warm water, Its modulus can be twice that of unreinforced PVC and equal to that of wood. PVC's high load carrying capability is not significantly increased to higher temperatures by adding glass fibers as judged by its 264 psi heat deflection temperature. However, by changing the polymeric matrix, glass reinforced vinyl with an increased HDT of 86°C has been produced for higher use temperature. The coefficient of linear thermal expansion of PVC can be cut in half by the addition of glass fibers and has a coefficient equal to that of aluminum. Glass fiber reinforced PVC has exceptionally good resistance to crack propagation and resists shattering as judged by sawing, punching, stapling, and hammering. When properly formulated for weathering resistance, glass fiber reinforced PVC has good color retention, impact retention, and outstanding dimensional stability. As for all glass fiber reinforced plastics, processing equipment must be built for high abrasion resistance for long economical manufacturing runs.     

What is Initiative?

This paper presents some alternate theories for explaining the term 'initiative', as it is used in the design of mixed-initiative AI systems. Although there is now active research in the area of mixed initiative interactive systems, there appears to be no true consensus in the field as to what the term 'initiative' actually means. In describing different possible approaches to the modeling of initiative, we aim to show the potential importance of each particular theory for the design of mixed initiative systems. The paper concludes by summarizing some of the key points in common to the theories, and by commenting on the inherent difficulties of the exercise, thereby elucidating the limitations which are necessarily encountered in designing such theories as the basis for designing mixed-initiative systems.     

Determination of oxygen in coal and coke using a radio-frequency heating method

Rapid procedures are described for the direct determination of organic oxygen in coal and coke at 1950 °C. Particular features include reduction—fusion of the sample in a radio-frequency heated, carbon-saturated iron bath, ease of attaining a steady blank rate, transference of the evolved carbon monoxide through a combined oxidation—purification system with argon carrier gas, and a gravimetric determination. The procedures are applicable to both demineralized and undemineralized samples, with a wide range of mineral matter contents. Results obtained for organic oxygen in a range of demineralized samples were in agreement with results obtained by the Unterzaucher—Oliver procedure. With coals of less than 5% mineral matter satisfactory agreement was achieved for demineralized or undemineralized samples or ‘by difference’; with coals of more than 5% mineral matter satisfactory agreements were obtained provided that a range of correction techniques for inorganic oxygen were used. Satisfactory results were obtained also for demineralized coke samples. Results for all techniques showed similar precision throughout the range of contents studied, with a standard deviation (1 s) of ca. 0.1% absolute.     

Accumulation of technetium-99 in the Irish Sea?

An assessment has been carried out to determine the impact of continued (99)Tc discharges into the Irish Sea from the nuclear fuels reprocessing plant at Sellafield. Samples of surface and bottom seawater and sediment have been collected from the Irish Sea and analysed for (99)Tc. The information has been used, together with supporting data, to determine the effect of summer stratification upon the seawater concentrations and to evaluate whether sediments provide a sink for (99)Tc. Hydrographic data provide clear evidence of thermal stratification of waters above the muddy sediment in the western Irish Sea. Surface water contained higher (99)Tc concentrations than bottom water, and concentrations were inversely related to water salinity. This inverse relationship was not observed in the eastern Irish Sea close to Sellafield. (99)Tc activities in surficial sediments were greatest (>20 Bq/kg) at sites closest to the Cumbrian coastline. Activity, from equivalent sampling sites, remained similar between surveys carried out in 1995 and 1998. The muted response of the seabed sediments, to fluctuations in the Sellafield discharges, compared with the water column is to be expected given that they reflect the integrated radionuclide discharge history.     

Fluorescence resonance energy transfer based MCM-EDTA-Tb3+-MES sensor

An in situ mesopourous surface imprinted polymeric (SIP) sensor was synthesized for a highly sensitive, selective, and kinetically faster detection of the high-vapor-pressure nerve gas surrogate methyl salicylate (MES). Visual detection occurred on the filtrate thin films at 25 pM. Other nerve gas surrogates, TP, DMP, DMMP, PMP, and 1,4-thioxane, were tested and showed a decrease in sensitivity compared to MES. In addition, 2,6-dipicolinic acid (DPA), a biological indicator, was also investigated and showed a decrease in sensitivity compared to MES. Finally, the detection plateau was reached at 40 s and at 1.5 x 10(-4) M from pH 6-11.     

Effects of 5 alpha-dihydrotestosterone and methandrostenolone in male guinea pigs

Young adult guinea pigs were studied 6 and 9 weeks after silastic capsules containing 5 alpha-hydrotestosterone (5 alpha-DHT) and methandrostenolone (Dianabol) were implanted. DHT was more effective in causing testicular atrophy and was apparently more androgenically potent in sustaining the size of the seminal vesicles. Both steroids led to hypertrophy of the masseter muscle and increase in gastrocnemius protein concentration. Cardiac tissue was sensitive to the effects of these steroids, particularly to the larger amounts of absorbed Dianabol, in terms of increases in DNA concentration and transient loss of tissue sodium, potassium, and calcium. All alterations in muscle composition occurred in the total absence of change in tissue water. Hypernatremia and hyperkalemia was present in steroid-treated animals with significant loss of urinary potassium in DHT-treated guinea pigs. Adrenal atrophy and the lowering of circulating cortisol was further indicative of effects upon adrenocortical function and the regulation of electrolyte balance.     

2,2′,6,6′-Tetrabromo-3,3′,5,5′-tetramethyl-4,4′-biphenol (TTB)–flame retardant copolycarbonates and copolyesters

2,2′,6,6′-Tetrabromo-3,3′,5,5′-tetramethyl-4,4′-biphenol (TTB) is a new flame retardant monomer possessing a high degree of chemical and thermal stability. This brominated biphenol can be directly incorporated as a comonomer in condensation polymerizations. An example is the preparation of copolycarbonates of TTB and 2,2-(4-hydroxyphenyl)propane (BPA) via the aqueous caustic phosgenation method. The reaction of TTB with either ethylene oxide or ethylene chlorohydrin affords 4,4′-bis(2-hydroxyethoxy)-2,2′,6,6′-tetrabromo-3,3′,5,5′-tetramethylbiphenyl (TTB-Diol). This diol is melt polymerized into a series of terephthalate copolymers with 1,4 butanediol. The above copolymers possess flame retardancy, thermal stability, and good mechanical properties. These high-bromine-content copolymers are blended with nonhalogen-containing polymers to afford blends with specific degrees of flame resistance.     

Solid-solution partitioning of plutonium in surface waters at the Atomic Weapons Establishment Aldermaston (UK)

The Atomic Weapons Establishment (AWE) at Aldermaston (Berkshire, UK) has provided and maintained the warheads for the UK's nuclear deterrent for more than 50 years. Whilst the site is radiologically safe, in a few locations the soil contains specific activities of plutonium (Pu) above background arising from a legacy of historic operations. Run-off water (a mixture of rainwater and groundwater) from part of the site is routed into a water management system, and after analysis and radiological assessment, released into local streams. Water and sediment samples have been collected from a number of closely spaced locations within this system to assess the solid-solution partitioning of Pu. Survey work was complemented by batch type desorption experiments to assess redissolution from 'contaminated' sediment into 'uncontaminated' water. The survey data indicate that specific activities of both dissolved and particle bound 239 + 240Pu varied by roughly two orders of magnitude, ranging from approximately 0.7 microBq kg(-1) up to approximately 44 microBq kg(-1), and approximately 1.2 Bq kg(-1) up to approximately 400 Bq kg(-1), respectively, consistent with water originating from different parts of the site. Apparent Kd values varied by an order of magnitude (from 0.7-16 x 10(6)) with an average value of 4 x 10(6). Results from the desorption experiments indicated the extent of redissolution was very small and the derived Kd's corroborated values obtained from the survey work. Kd's given here are compared with other literature values, and are the greatest reported to date. Results are also provided describing the variation in water quality parameters in shallow groundwater samples. Alkalinity values ranged from 120 to 388 mg l(-1) CaCO3 with an average value of 195 mg l(-1) CaCO3. Corresponding values for pH were 6.6-8.3 with an average of 7.5. Over half of the samples were estimated to be supersaturated with respect to calcite. It is suggested that the state of calcite saturation may be responsible for the high Pu Kd. As a consequence of the high particle reactivity, migration of Pu contamination, both within and away from the AWE Aldermaston site, is likely to be very restricted.     

In situ surface-etched bacterial spore detection using dipicolinic acid-europium-silica nanoparticle bioreporters

A basic approach was optimized for the synthesis of highly selective and sensitive in situ mesoporous (MCM) type imprinted silica polymers for the detection of dipicolinic acid (DPA) using europium as a reporter. DPA is a ubiquitous biochemical marker available during the germination event of endospore-forming bacteria such as Bacillus . Additionally, an MCM-MIP (molecularly imprinted polymeric phenomena) detector and a companion MCM-non-surface-MIP detector were synthesized using europium reporters for the sensing of DPA under optimized laboratory conditions. Our results showed that the in situ molecular imprinting process enabled rapid, selective detection of DPA with high sensitivity compared to MCM-MIP (imprinted for DPA; no DPA present), MCM-Non-MIP (no imprint present), and MCM-SR-MIP (imprinted with DPA present) detectors. The lower detection limit observed for DPA concentration is 5.49 × 10(-10) mol dm(-3) for MCM-MIP. The performance of the sensor in high-salt-water conditions, under photo-bleaching, and its reusability were also evaluated. The synthesized in situ MCM-MIP material should permit the detection of DPA for field assays related to suspect bacterial sporulation events.