13C and 1H n.m.r. study of the polyesterification of maleic anhydride and 1,2-propylene glycol

The reaction steps of the polyesterification of maleic anhydride and 1,2-propylene glycol were followed by ¹³C and ¹H n.m.r. spectroscopy. The number and structure of mono- and diesters of both maleates and fumarates in the reaction mixture are determined by the possible glycol unit configurations. The structure of the growing polyester chain reflects a statistical distribution of approximately equal numbers of symmetric and asymmetric arrangements of the polymer sequences.     

Triacylglycerols composition of oil in OS soybean cultivars

Oil content in grain and triacylglycerol composition of several Croatian soybean cultivars (Glycine max (L) Merrill) was investigated. Trials were conducted at two localities during three years and involved seven soybean cultivars. All investigated cultivars were created in soybean breeding program at the Agricultural Institute Osijek in Croatia. Oil content in grain was determined by NMR method. Triacylglycerols were analyzed by reversed phase high performance liquid chromatography with refractive index detector and identified by comparing their retention time to standards.Oil content was similar in soybean cultivars within year and localities but varied significantly among years. Chromatograms of every injected sample showed 15 individual triacylglycerol peaks, and the main components are trilinolein, dilinoleoolein, and dilinoleopalmitin. A small difference of triacylglycerol composition was noticed among soybean cultivars whereas larger one was noticed among the investigated years. The obtained results will be able to use in further breeding work for soybean cultivars grain quality improvement.     

Interorganizational GIS: Issues and prospects

Better analysis and understanding of local and regional phenomena can result from large scale data built by a variety of local government agencies and private sector organizations. Reducing duplication and saving organizational resources are two main arguments for sharing geographic data and systems. This, however, is quite challenging and requires extensive interorganizational coordination. Drawing on existing literature and focusing primarily on local government settings, this paper reviews the major issues related to coordinated development and use of local geographic information systems and databases. These issues include motivation for sharing, coordination process, organizational factors, standardization and interoperability, cost of coordination, and mechanisms for GIS sharing.     

Effect of gamma irradiation on the dielectric relaxation of uniaxially oriented low density polyethylene

The dielectric loss tangent of unirradiated and irradiated low density polyethylene (LDPE) samples was measured as a function of temperature, from 50 K to room temperature, in directions normal and parallel to that of drawing. The influence of drawing and irradiation on the β‐relaxation and γ‐relaxation are related to the changes in the structure of the amorphous phase and lamellae distribution, and to the radiation‐induced processes of degradation and crosslinking. © 1999 Society of Chemical Industry     

A knowledge-based test plan generator for incremental unit and integration software testing

Unit and integration testing are two expected levels of testing for conventionally designed programs. This article presents a system for the automatic generation of test plans for incremental unit and integration testing. Starting from a global task of planning integration testing, the system generates a detailed test plan automatically for a given program on the basis of its decomposition as a software structure. The system is implemented as a frame-based system. It supports four standard ways of assembling units during integration, and two ways of testing according to parallelism. It also takes into account the units that require more testing than others. The system greatly improves the productivity of planning integration testing in comparison with the current practice of producing test plans manually. Experiments have shown a minimum productivity increase of 55 times. © 1998 John Wiley & Sons, Ltd.     

Efficient and novel Sb2S3 based solar cells with chitosan/poly(ethylene glycol)/electrolyte blend

We present here a novel solar cell made of ITO/composite p‐doped Sb₂S₃ + P3HT + PANI+TiO₂/amorphous Sb₂S₃ + P3HT + PANI + TiO₂/n‐doped Sb₂S₃ + P3HT + PANI + TiO₂/solid carrier/aluminum as counter electrode. With spraying technique, the layers were deposited and the thickness of films was 1 μm. A new solid carrier of electrolyte was a blend consisted of chitosan (low MW), polyethylene glycol and electrolyte. X‐ray diffraction was recorded to confirm the amorphous nature of the blend. Information about the surface appearance and roughness of a solid carrier dry and soaked in the electrolyte was given by atomic force microscopy. The solar cell was examined at very low and low light intensity (5% and 35% of sun, respectively), and at standard test conditions (100% of sun) using different light sources. The whole cell surface was 7.5 cm² while the illuminated part was 3 cm². Obtained results expressed for the illuminated surface showed the highest efficiency of 23.1% at 5% of sun while the efficiency of the cell was 2.9% at 35% of sun and only 0.75% at intensity of 100% of sun.     

Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins

The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 ± 0.2 kHz and an amplitude of 40%) for 2–20 min on the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from ～370 to ～260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.

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