Analysis and optimization of solar hot water systems

Use of a simplified method has been made to calculate the time-dependent thermal performance of various solar domestic hot water systems. to establish the value of solar hot water systems under given economic considerations a thermal analysis was carried out on three basic energy system designs, operating at several locations in the Federal Republic of Germany (F.R.G.) with various solar collectors. It is found that systems design can result in variations up to a factor of two in the per cent solar output. the location and year of operation in the F.R.G. result in variations up to 15 per cent in the solar output. A sensitivity study was also done with respect to all solar collector, systems and user parameters. From this it was found that the dominant effects on the systems performance were due to the collector-dependent parameters.     

Power Filter Insertion Loss Evaluated in Operational-Type Circuits

Insertion losses of several different manufacturers' 100-ampere power filters were measured in the frequency range 100 Hz to 2 MHz and at a range of power current loads utilizing a newly developed current injection probe. The measurements were made using a technique which, in compliance with IEEE measurement standards, provides a constant voltage source in a filter-in filter-out measurement circuit, where source and load impedance parameters are known. Theoretically derived curves for the power filters installed in circuits with complex source and load impedance are compared to measured curves. Theoretically derived curves for current or voltage attenuation are also compared to insertion loss curves. Significant departures from the MIL-STD-220A specification curves were obtained using this new current injection probe measurement method. Strong saturation effects were found with several of the filters. Wide passband excursions were obtained as predicted by the theoretical treatment. The new measurement technique is described in terms of its relation to IEEE standard definitions of insertion loss. A discussion is given of present and proposed methods in relationship to what is felt is the most useful means of describing a filter's operational characteristics.     

The LEMMA concept: A new manipulator

The LEMMA is a proposed conceptual design of a remote teleoperator manipulator arm with 6 degrees of freedom, exclusive of the end-effector. The bevel gear arrangement in 4 of the 6 degrees of freedom, together with the concentric-tubular arm configuration, requires a unique and a novel drive mechanism. This differential drive assembly, housed in the shoulder, is a self-compensating device and simplifies the matrix solution for the resolved motion rate control system needed to guide the arm in its performances. The article will describe the need for the 6 degrees of freedom as established by the work envelope, the functioning of the differential shoulder drive, the arm and joint configuration, and the anticipated degree of accuracy.     

Differences in visual perception and in visual-motor functioning between psychotic and nonpsychotic children.

The study explored the applicable scope of Bender's theory of a "maturational lag" in functional childhood psychosis. Tests of visual perception, visual-motor performance, and a clinical evaluation of presence of CNS deviations consistent with Bender's criteria for childhood schizophrenia were performed on 39 psychotic and 57 nonpsychotic 8-12-year-old boys. Results revealed no differences in accuracy or variability of perceptual and visual-motor behavior when appropriate controls for large group differences in MA functioning were instituted. No difference in test performance was found between psychotic Ss with and without CNS deviations. With MA level constant, the difference in incidence of CNS deviations between psychotics and nonpsychotics was nonsignificant. The results were interpreted as not supporting Bender's organic theory. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

C-terminal modifications of a protein by UAG-encoded incorporation of puromycin during in vitro protein synthesis in the absence of release factor 1

Deactivation of release factor 1 by polyclonal antibodies in an in vitro translation system, which was used to express the esterase gene, led to the reversible elimination of naturally occurring termination. This technique allowed the antibiotic puromycin to be used as an acceptor substrate for the peptidyl residue in the peptidyl-transferase reaction. This resulted in more than 80 % yield of protein with C-terminally incorporated puromycin. pCpPuromycin that was either conjugated with the Cy3 fluorophor or biotin by N4 alkylation of cytosine, also acted as an acceptor substrate for the peptidyl-transferase reaction and was incorporated into the protein C terminus. The resulting conjugates possessed Cy3-specific fluorescence and affinity to streptavidin-coated surfaces, respectively. This left the enzymatic activity of the reporter protein unaffected. It was also shown that extension of puromycin on its 5'-hydroxyl end by up to ten deoxyoligonucleotides also allowed conjugation with the C terminus of in vitro translated protein when RF1-dependent termination was suppressed. However, the conjugation yield decreased upon addition of more than six nucleotides.     

Rapid Analysis of Abietanes in Conifers

Diterpene resin acids are major constituents of conifer oleoresin and play important roles in tree defense against insects and microbial pathogens. The tricyclic C-20 carboxylic acids are generally classified into two groups, the abietanes and the pimaranes. The abietanes have conjugated double bonds and exhibit characteristic UV spectra. Here, we report the analysis of abietanes by reversed-phase high-performance liquid chromatography using multiwavelength detection to optimize quantification of underivatized abietic, neoabietic, palustric, levopimaric, and dehydroabietic acids. The utility of the method is demonstrated with methanol extracts of white spruce (Picea glauca) phloem, and representative concentrations are reported.     

20 Jahre IT-Sicherheitszertifizierung

In den drei vorausgegangenen Teilen dieser Beitragsserie ging es um die Motivation und Etablierung der beh?rdlichen und privaten Zertifizierungsschemata in Deutsch land. In diesem letzten Teil betrachten die Autoren die aktuelle Entwicklung und m?gliche Perspektiven.     

Vorkommen von Vanadium im Grundwasser der Vulkaneifel

Grundwasser - In Quellwasserproben rund um den Ringseitert-Vulkankomplex südöstlich der Gemeinde Kirchweiler (Westeifel) wurden weit über dem Geringfügigkeitsschwellenwert...