Evaluation of patient improvement in a token economy treatment program.

Investigated various indices of improvement in 20 female chronic mental patients (mean age = 36 yrs) who were randomly assigned to a token economy treatment ward as compared with 20 control patients who received typical custodial treatment. All Ss were given standardized interviews consisting of 5 experimental tasks. Segments of the interviews were video-recorded and rated by naive raters on a 20-item questionnaire. Results indicate that the token-economy Ss were better oriented, had more skill in making business purchases and discriminations, and were better able to follow commands. Token economy Ss were rated as being more cooperative and communicative, more socially desirable, more appropriate in mood, and as exhibiting less psychotic behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extracting dust from soil: a simple solution to a tricky task

Air quality is commonly assessed by the ambient concentration of airborne particles sized smaller than 10 microm (PM10). However, in addition to concentration, particle shape as well as the type and bioaccessibility of elements adsorbed to this particulate fraction are likely to be related to subsequent respiratory health effects. In order to investigate this relationship, a relatively large mass of the relevant size fraction is needed since sample preparation is necessary prior to analysis. Most existing methods for sampling dust have been developed for analysing the dust directly, without prior handling or digestion. In order to provide sufficient material to be used for subsequent bioaccessibility analysis, these methods require repetitive and time consuming sampling as well as special equipment and procedures which are high in both cost and maintenance. This paper describes an inexpensive and relatively simple procedure for extracting the PM10 fraction from soil to be used for lung bioaccessibility studies. The method described involves dry and wet sieving in order to exclude larger size fractions as far as possible. Vacuum filtering of the wet-sieved soil solution through a 10 microm mesh was then employed to extract the required fraction. In order to avoid frequent blocking of the mesh, Stokes's law was applied in the construction of a tube which enables separation of the solution holding the smallest fraction.     

Chemical reactions and applications of the reductive surface of porous silicon

The chemical reactivity of freshly prepared porous silicon is similar to that of a reducing agent on the surface of the nanocrystallites. Ag+ spontaneously reduces to form Ag0 granular coatings on the surface of porous silicon at the expense of the oxidation of silicon hydride and silicon. Atomic Force Microscopy shows that the thickness and topography of the Ag0 coating depend on the concentration of Ag+ with the porous silicon surface being the limiting reagent. In-situ Raman Spectroscopy shows an Ag layer on the silicon and Si:O layer immediately after etching and exposure to Ag+ and O2 respectively. Ag0 coated on the surface and in the pores of the porous silicon proves to be an excellent material for Surface Enhanced Raman Spectroscopy and the natural low electron affinity on the surface of porous silicon replaces the need for a negative bias to prepare very stable diamond coatings on the surface of silicon.     

Wear and Friction of Filled Polytetrafluoroethylene Compositions in Liquid Nitrogen

Wear and friction behavior of slider materials at cryogenic temperature is important to the development of seals and bearings for missile powerplants. Data were obtained in liquid nitrogen (?320°F) with a series of molded and extruded polytetrafluoroethylene (PTFE) compositions containing various filler materials. A 3/16-in. radius rider specimen (PTFE materials) was caused to slide in a circumferential path on the flat surface of a rotating 2½-in. diameter disk specimen (usually type 304 stainless steel). The sliding velocity was usually 2300 ft per min and the load was 1000 grams.

As compared with reference steels and carbons used in conventional seals and bearings, the filled PTFE compositions gave low wear and friction (friction coefficients from 0.06 to 0.13) in liquid nitrogen. Several extruded compositions have particular promise for seal and bearing materials. An extruded glass-filled material gave wear and friction that was essentially unaffected by sliding velocities to 6000 ft per min.     

Fabrication and characterization of Ti-Ba-Ca-Cu-O superconducting films on LaAlO3 substrates

A multi-step process is used to fabricate Tl₂Ba₂Ca₁Cu₂O₈ films on (100) LaA10₃ substrates. Submicron thick precursor films of Ba-Ca-Cu-O are rf magnetron sputter deposited from a single target. Film stoichiometry is measured by ion beam backscattering spectroscopy. Deficiencies of the alkaline earths that are found in the precursor films are then compensated for by the addition of appropriate CaF₂ and/or BaF₂ films onto the surface of the precursor film. Post deposition annealing of the films is then done in an atmosphere of thallium oxide and oxygen in order to form the superconducting phases. The annealed films are examined using x-ray diffraction (XRD), an ac inductance technique, and critical current in an external magnetic field. XRD shows the c-axis length of the superconducting phase to increase as the overall film stoichiometry approaches 2212. The transition widths measured by inductive coupling weakly correlate with 77 K critical current measurements. Our best critical current results are 1.5*10⁶ amps/ cm² for a film measured at 4 K in an 8 T magnetic field (parallel to the films' c-axis).     

Managing the flow of intelligent parts

Advances in computer technology have brought the feasibility of intelligent system components to fuitation. Within the manufacturing environment, the regulation of parts' value-adding operations from entry into the system to completion as a finished product now can be individualized to depend on part specific information. The new CADENCE system, introduced in this research, manages the physical parts' operations and the information flow within manufacturing. Integration of both the physical flow dependencies and the information flow is provided by a negotiation procedure. CADENCE goes beyond previously proposed task bidding structures by utilizing distributed decision making in managing the flow of individual intelligent parts.     

Hydrogen dissociation below 1 K

We report on an investigation of hydrogen dissociation at dilution refrigerator temperatures. The objective of this study is to develop a low-temperature hydrogen atom source for experiments on spin-polarized atomic hydrogen. We find that, in a discharge tube coated with a solid H₂ layer and a superfluid He film, hydrogen dissociation is mediated by a glow discharge supported by He vapor. The He discharge provides the energetic particles needed for removing H atoms from the solid H₂ coating. In order to strike a He discharge, the He vapor pressure has to correspond to a wall temperature of 0.60–0.75 K. The best results are obtained close to the low-temperature threshold for ignition, or at even lower temperatures if the rf discharge pulse is preceded by a heat pulse adjusted to flash-evaporate the required initial He density. Hydrogen atom yields of 10¹³ H/discharge pulse are typical, and scale with the pulsed rf energy as long as the discharge volume is not overheated and remains in good thermal contact with its cooling jacket. In these conditions the H flux from the dissociator is proportional to the average rf power with a dissociation efficiency of 3%. With a dilution refrigerator circulation of 0.3 mmole/sec of³He, H fluxes of 5×10¹³ H/sec are obtained in steady-state discharge conditions.Deceased March 1986.