Design of nonaxisymmetrical image intensifiers

The concept of a nonaxisymmetrical X-ray image intensifier is presented in this paper. Instead of cylindrical electrodes, as in the conventional device, this intensifier is equipped with planar electrodes. Each one consists of some number of elementary quadrilateral patches, which are mutually insulated from each other and supplied with the proper voltages. The algorithm for determining potentials which must be supplied to the elementary electrodes is described in the paper. The algorithm has been validated by comparing the electric field distributions in both configurations. Details of the electric field distribution are also helpful in evaluating the optical characteristics of the intensifier     

Further study on the one-pot synthesis of (E)-2-nonenal from castor oil

A one-step procedure is described for the synthesis of (E)-2-nonenal from commercial castor oil by ozonolysis in methanol, followed by reduction of the ozonide products with dimethyl sulfide and exposure of the resulting intermediate product to dilute sulfuric acid. The developed process allows the production of the aldehyde with a yield of 80% at a purity of 95%. The method has advantages over all those reported earlier, because of inexpensive raw material and reducing agent, recycling of the solvent and its unusual simplicity.     

Intelligent product search with soft-boundary preference relaxation

This paper proposes a novel method for preference relaxation in online product search, which enables consumers to make quality choices without suffering from the commonly experienced information overload. In online shopping scenarios that involve multi-attribute choice tasks, it can be difficult for consumers to process the vast amounts of information available and to make satisfactory buying decisions. In such situations consumers are likely to eliminate potentially good choices early on, using hard-constraint filtering tools. Our approach uses edge sets to identify the alternatives on the soft boundary and the principle of alternative domination to suppress the alternatives on this boundary that are irrelevant. We demonstrate how our approach outperforms existing methods for product search in a set of simulations using two sets of 2650 car advertisements and 1813 digital cameras gathered from a popular online store.     

A novel functional silica/lignin hybrid material as a potential bio‐based polypropylene filler

A functional silica/lignin hybrid filler was obtained using a process of mechanical grinding of precursors (Syloid^®244 silica and kraft lignin). The product underwent comprehensive physicochemical and dispersive–morphological analysis. The silica/lignin hybrid has good homogeneity and a surface area of 164 m²/g. The effectiveness of combination was confirmed by Fourier transform infrared spectroscopy and elemental analysis. The high electrokinetic stability (over almost the whole of the analyzed pH range) and above all the thermal stability of the resulting material (mass loss equal to 12%) indicate its potential use as a polypropylene (PP) filler. Experiments showed that the incorporation of a small amount of silica/lignin hybrid filler into PP may substantially influence its elongation at break and notched impact strength. Especially at low concentrations of silica/lignin filler (below 5 wt%) an exceptional set of mechanical properties was obtained. The addition of larger amounts of the filler was found not to bring any further improvement. POLYM. COMPOS., 36:913–922, 2015. © 2014 Society of Plastics Engineers     

Wideband Low‐Reflection Transmission Lines for Bare Chip on Multilayer PCB

The pad pitch of modern radio frequency integrated circuits is in the order of few tens of micrometers. Connecting a large number of high‐speed I/Os to the outside world with good signal fidelity at low cost is an extremely challenging task. To cope with this requirement, we need reflection‐free transmission lines from an on‐chip pad to on‐board SMA connectors. Such a transmission line is very hard to design due to the difference in on‐chip and on‐board feature size and the requirement for extremely large bandwidth. In this paper, we propose the use of narrow tracks close to chip and wide tracks away from the chip. This narrow‐to‐wide transition in width results in impedance discontinuity. A step change in substrate thickness is utilized to cancel the effect of the width discontinuity, thus achieving a reflection‐free microstrip. To verify the concept, several microstrips were designed on multilayer FR4 PCB without any additional manufacturing steps. The TDR measurements reveal that the impedance variation is less than 3 Ω for a 50 Ω microstrip and S11 better than –9 dB for the frequency range 1 GHz to 6 GHz when the width changes from 165 µm to 940 µm, and substrate thickness changes from 100 µm to 500 µm.     

Methodological hints on the gas chromatographic determination of kelevan and kepone in potatoes, potato foliage and soil]

The gas chromatographic determination of Kelevan, an ethyllaevulinic acid derivative of Kepone, requires its conversion to Kepone. Thermal decomposition in the injection block of the gas chromatograph at 45 degrees C. has proved to be well suited for routine work. The sample is extracted with acetonitrile; the extract is purified and concentrated under reduced pressure. The separation of Kelevan from Kepone already metabolically produced is possible by column chromatography (silica gel; elution with benzene and 5% acetone in benzene). The determination of pre-existent Kepone and of Kelevan (after thermal conversion to Kepone) was achieved by means of a Pye-Unicam gas chromatograph. The limits of detection are 0.002 p.p.m. for Kepone, and 0.003 p.p.m. for Kelevan. The recovery of Kelevan and Kepone added to control samples (for every 10 determinations with different amounts added to potatoes, potato foliage and soil samples) ranges from 63 to 88%; the standard derivation, from +/- 1.7 to 7.3%.     

Can Economics-based Resource Allocation Prove Effective in a Computation Marketplace?

Several companies offer computation on demand for a fee. More companies are expected to enter this business over the next decade, leading to a marketplace for computation resources. Resources will be allocated through economic mechanisms that establish the relative values of providers and customers. Society at large should benefit from discoveries obtained through the vast computing power that will become available. Given such a computation marketplace, can economics-based resource allocation provide benefits for providers, customers and society? To investigate this question, we simulate a Grid economy where individual providers and customers pursue their own ends and we measure resulting effects on system welfare. In our experiments, customers attempt to maximize their individual utilities, while providers pursue strategies chosen from three classes: information-free, utilization-based and economics-based. We find that, during periods of excess demand, economics-based strategies yield overall resource allocation that benefits system welfare. Further, economics-based strategies respond well to sudden overloads caused by temporary provider failures. During periods of moderate demand, we find that economics-based strategies provide ample system welfare, comparable with that of utilization-based strategies. We also identify and discuss key factors that arise when using economic mechanisms to allocate resources in a computation marketplace.     

Assay of ascorbic phosphates and in-vitro availability assay of ascorbic mono-and polyphosphates

A method was devised to assay ascorbic phosphate esters in biological materials by potassium bromoxide hydrolysis followed by determination of the liberated ascorbic acid. For the differential measurement of ascorbic acid and ascorbic phosphate, a spectrophotometric method was employed to screen out the interfering substances based on studies of absorbance curves of 2,4-dinitrophenyl hydrazine derivatives. A variety of vertebrate tissues were examined for phosphatase activity on ascorbic phosphate esters. The results suggest that pigeon kidney, rat liver and several tissues of fishes readily hydrolyse ascorbic monophosphate but not ascorbic polyphosphate. Hydrolysis of ascorbic monophosphate is completed by both phosphatases of intestine, kidney and liver acting at neutral pH and phosphatase of stomach acting at acid pH. Thus, ascorbic monophosphate has the potential to be a source of available vitamin C in vivo, and this explains its antiscorbutic activity in scurvy-prone animals.