Inorganic-melt-catalysed hydrogenation of phenanthrene

The hydrogenation of the coal model compound phenanthrene was investigated using a molten hydroxide-carbonate catalyst. The rate of catalysed hydrogenation was found to be approximately an order of magnitude greater than the uncatalysed reaction. Batch experiments were conducted at 20.7 MPa hydrogen pressure in a 1-l top-stirred autoclave at 480 °C for reaction times up to 1 h. Spinning-band distillation and gas-liquid chromatography coupled with mass spectrometry were used to separate and identify reaction products. Principal hydrogenation products were 9,10 dihydrophenanthrene and 1,2,3,4-tetrahydrophenanthrene. In addition, substituted naphthalenes and biphenyls were formed by hydrocracking of these two compounds. A similar product distribution was reported by others for an investigation of the thermal high-pressure hydrogenolysis of phenanthrene. The rate of the thermal reaction, however, was considerably lower.     

A measure of the effect of drying temperature on the selenium content of herbage

Selenium was determined on samples of grassland herbage, subdivided and dried at different temperatures. Statistical examination of the results showed that the temperature of drying had no significant effect.     

Porous ceramic bone scaffolds for vascularized bone tissue regeneration

Hydroxyapatite scaffolds with a multi modal porosity designed for use in tissue engineering of vascularized bone graft substitutes were prepared by three dimensional printing. Depending on the ratio of coarse (mean particle size 50 microm) to fine powder (mean particle size 4 microm) in the powder granulate and the sintering temperature total porosity was varied from 30% to 64%. While macroscopic pore channels with a diameter of 1 mm were created by CAD design, porosity structure in the sintered solid phase was governed by the granulate structure of the printing powder. Scaffolds sintered at 1,250 degrees C were characterized by a bimodal pore structure with intragranular pores of 0.3-0.4 microm and intergranular pores of 20 microm whereas scaffolds sintered at 1,400 degrees C exhibit a monomodal porosity with a maximum of pore size distribution at 10-20 microm. For in-vivo testing, matrices were implanted subcutaneously in four male Lewis rats. Scaffolds with 50% porosity and an average pore size of approximately 18 microm were successfully transferred to rats and vascularized within 4 weeks.     

Ionospheric tomography algorithms

The relatively recent development of inexpensive, high-speed computational resources has made computerized tomography a readily accessible tool for remote sensing. A variety of geophysical remote applications have made use of the technique; in particular, tomography has been used to image the electron density in the Earth's ionosphere. As in most cases there are problems unique to the application. A review of the algorithms used to date is presented with a sampling of experimental results.©1994 John Wiley & Sons Inc     

Adverse Effects of Predictive Testing for Huntington Disease Underestimated: Long-Term Effects 7-10 Years After the Test.

The 7-10-year psychological effects of presymptomatic testing for Huntington disease are described in 142 individuals and 104 partners. Questionnaires included the Beck Hopelessness Scale (A. T. Beck, A. Weissman, D. Lester, & L. Trexler, 1974), the Impact of Event Scale (M. J. Horowitz, N. Wilner. & W. Alvarez. 1979). and the General Health Questionnaire (D. P. Goldberg. 1972). Carriers and their partners were more distressed immediately after the test result, although their outlooks improved somewhat in the 2-3-year posttest period. However, they became more pessimistic thereafter, when approaching the age of onset. Carriers, who were lost to follow-up after disclosure of test results, reported more distress pretest than did retained carriers. This demonstrates that studies that report few harmful effects may have underestimated the real impact. Moreover, follow-up studies need to investigate time effects for longer than a few years. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Endurance of gel‐filled silicone breast implants as a function of maximum load in cyclic compression tests

The mechanical behaviour of gel‐filled silicone breast implants is examined under compressive load. First the implants are tested by applying various loads in a repetitive fashion until shell rupture occurs. Subsequently the results are presented allowing an assessment of the correlation between the number of loading cycles and the maximum compressive load. Finally it is possible to estimate the endurance of the silicone breast implants. Using a power law, a correlation between endurance and maximum load is revealed. © 2018 Society of Chemical Industry     

Compressive and cyclic loading of silicone breast implants and their effect on shape resilience and reliability of the shell material

The mechanical behavior of gel‐filled silicone breast implants has been examined as well as the mechanical properties of the implant shell itself. For the first time the implants were tested under compression in two different ways. Subsequently the implant shell material was analyzed by tensile test on dumbbell‐shaped specimens. The results are presented in contour plots which provide a detailed view of the measured values of the samples. Finally a statistical failure analysis was carried out by means of a Weibull fit to provide further data on the mechanical behavior. © 2017 Society of Chemical Industry     

Rechnergestützte Konfigurierung von RI-Fließbildern am Beispiel von Pumpen

Knowledge-based Design of PI Diagrams Exemplified for Pumps in Chemical Plant. To date, computer-aided design for flow-sheets has focussed on drawing procedures and reports extracted from these drawings. Today's software technology offers important potential which has still not been fully exploited, e.g. for the design of PI diagrams as front-end application of CAD systems. PI diagrams for process units can be designed by means of knowledge-based systems. The input information which has to be supplied by the process engineer comprises e.g. physico-chemical properties, process conditions and start-up and shut-down procedures. The results are PI diagrams as well as the documentation of the design criteria and operating instructions if manual operations on site are necessary. The potential of knowledge-based computer-aided design of PI diagrams is demonstrated in the case of pumps in chemical plant.