Development of switching principles and phase comparison techniques for distance protective schemes

The paper represents further work on phase comparison techniques by the same author. Two techniques are reported here. The first one describes a new principle of operation employed for the main functions of starting elements for fault detection and selection of phase(s). The principle is based on a process of phase comparison accomplished between comparison quantities derived from the three symmetrical components of line current relative to only one phase of the protected line section. Fault detection and phase selection are achieved by delivering nine distinct orders from the starting element corresponding to the nine cases of asymmetrical faults. The starting element based on this principle reduces the switching time to 3.33 ms.The second technique is concerned with phase comparison techniques to improve the security and reliability of the high-speed comparator described previously by the same author. The modus operandi consists of continuously monitoring the coincidence of compared comparison periods derived from the two relaying signals and simultaneously the non-coincidence of another set of compared comparison periods derived from the same relaying signals. Fault detection is achieved by delivering a trigger output from the comparator corresponding to non-coincidence of the first set and coincidence of the second set of comparison periods.     

Applications nouvelles de la matrice des lignes de transmission: Sélection des modes dans les lignes microondes caractérisation des éléments rayonnants

The transmission line matrix method permits modification of the excitation of modes in microlines. This property gives access to phase velocities by synchronisation of excitation and propagating modes. The selection of modes is possible by this synchronisation. Group velocities are deduced from frequency modulation due to geometrical dimensions variation. In another part, two methods of infinited space simulation are proposed. Applications about radiation patterns of the dipole antenna and the half dipole are given. The input impedance and the resonance frequency are calculated for a printed strip dipole.     

Nutritional quality of uncultivated cereal grains utilised as famine foods in western sudan as measured by chemical analysis

The chemical composition of the grain of a number of wild grasses used as food in times of famine in western Sudan are reported and compared with those of the local staple cereals. Species investigated were Cenchrus hiflorus (haskaneet). Dactyloctenium aegyptium (korecb). Echinochloa colona (difra) and Oryza punctata (ruz el wadi). The grain of all species except C biflorus had protein contents in the range 110-140 g kg^?1, broadly similar to those of the local staple cereals. The grain of C biflours possessed a particularly high protein content of 210 g kg^?1. The nutritional quality of the proteins as measured by their chemical scores ranged from 20 for C biflorus to 65 for O punctata compared with scores of 36 and 58 for the local sorghum var Kurgi and millet respectively. Lysine was the limiting amino acid in all cases. Whilst the composition of the protein of sorghum var Kurgi was typical of sorghum generally, that of var Karamaka was unusual in possessing lysine levels of 3.4 g (16 g N)¹, double that normally present in sorghum and raising the chemical score of the protein to 62. The ash content of the famine food cereals was high, attaining 113 g kg¹ in C biflorus. All grains were good sources of zinc and D aegyptium. O punctata and E colonum additionally contained comparatively high levels of iron. Remarkably for a cereal D aegyptium was also very rich in calcium, containing over 10 g kg¹, and possessed high concentrations of manganese. Carbohydrate content of the famine food grains varied from 617 g kg¹ for C biflorus to 748 g kg¹ for O punctata, values comparable to the local staple cereals. The proportion of starch in this fraction ranged from 650 g kg¹ in D aegyptium to 940 g kg¹ in O punctata. Seed oils of all species were predominantly unsaturated containing mainly oleic and linoleic acids.     

Microstructure,free amino acids and free fatty acids in Ras cheese

The physical state of the protein in Ras cheese has been followed by TEM and SEM in parallel with the chemical changes during maturation. The microstructure of young Ras cheese, by TEM, consists of casein micelles joined to form an open network, with some clustering of the micelles that appear, by SEM, as thin fibres aggregated into cross-linked elongated strands. At higher magnification, the casein fibres appear folded to include cavities.With further maturation to 4 months, the cheese matrix changed considerably by dissociation of the casein micelles to form a more homogeneous structure of sub-micelles, as seen by TEM, whilst SEM micrographs indicated that some protein fibres still existed.The protein breakdown, the accumulation of free amino acids and the liberation of free fatty acids in Ras cheese increased during maturation by decomposition of paracasein and cheese fat.Ras cheese is characterized as a compact body but can be viewed as an extensive inter-connection between the casein sheets in a cheese matrix and by a sharp flavour attributed to free glutamic acid and the presence of butyric, caprylic and caproic (free volatile) fatty acids.     

Delayed positive thallium uptake in large B-cell non-Hodgkin's malignant lymphoma

We report an unusual finding in an AIDS patient who presented with a large mediastinal mass and multiple lymphadenopathy. A sequential thallium and gallium scan to specify the nature of the mediastinal mass was requested. The early thallium images, acquired 15 min after the intravenous injection, showed no uptake in the mass. The delayed images 2 hr later showed intense thallium uptake. A gallium scan performed 48 hr later also showed intense gallium uptake in the mediastinal mass. Biopsy from the inguinal lymph node confirmed the presence of large-cell diffuse noncleaved malignant lymphoma. This case raises questions about the optimum time of imaging for thallium in high-grade lymphoma, whether delayed imaging is essential, about previous reports of low sensitivity of thallium in undifferentiated lymphoma and about the mechanism of thallium uptake in this type of tumor.     

Solid solution phases from thermally crystallized Li2O-MgO-Al2O3-SiO2 glasses

Phase transformations have been studied in glasses related in composition to Li₂O-MgO-SiO₂ (930° C) eutectic glass modified by $\text{Al}{}_2\text{O}{}_3\text{Li}{}_2\text{O}$ replacement on a cation per cation basis. Crystallization processes and changes in the solid solutions of the mineral phases developed during the controlled heating of the glasses have been followed using X-ray and microscopic techniques.Solid solutions of lithia aluminosilicate phases (B-eucryptite and/or B-spodumene s.s.) are the essential minerals that crystallize in glasses through most of the heat treatment applied. Lithium metasilicate, disilicate, clinoenstatite and cordierite are also encountered.B-eucryptite s.s. is formed in early stage of crystallization of the glass which transforms into B-spodumene s.s. at higher temperature (800° C). However, in some cases, it persists at temperatures as high as 1000° C.Metastable B-eucryptite-B-quartz s.s. can accomodate considerable amounts of Mg²⁺ and Al³⁺ ions in its lattice especially at lower temperature. At higher temperature for long duration, a redistribution of the elements takes place, and the cordierite phase then developed.     

Sensitive detection of sulfhydryl groups in surface-confined metallothioneins and related species via ferrocene-capped gold nanoparticle/streptavidin conjugates

Metallothionein (MT), a cysteine-rich metalloprotein that is purported to play an important role in heavy metal accumulation and detoxification, and its related peptidic species were attached onto dithiobissuccinimidyl propionate self-assembled monolayers. The spatially accessible sulfhydryl groups present in these immobilized biomolecules, tagged with N-biotinoyl-N'-[6-maleimidohexanoyl]hydrazide, were detected voltammetrically at a sensitive level via the use of ferrocene (Fc)-capped gold nanoparticle/streptavidin conjugates. The method was established first by examining relatively simple peptides (e.g., glutathione). For the hexapeptidic species that resembles the N-terminus of MT with a sequence of Lys-Cys-Thr-Cys-Cys-Ala, concentration levels as low as 0.050 nM can be determined. Such a remarkable sensitivity is attributed to the presence of a large number of Fc caps present at each gold nanoparticle, which enhances the detection of a small number of surface-bound sulfhydryl groups. Microgravimetric measurements, performed with a quartz crystal microbalance, were used in tandem with voltammetry to quantify the number of tagged sulfhydryl groups. Through extraction of the metals present in MT adsorbate, it is demonstrated that this amplified voltammetric detection is also suitable for the investigation of the variation of the number of sulfhydryl groups present at an electrode and sensitive to the change of surface structure of an immobilized biomolecule. This work represents a new method for the determination of sulfhydryl groups inherent in surface-bound proteins or peptides and can facilitate the study on the environmental issues related to MTs.     

Third-generation virtualized architecture for the MVNO context

The third-generation architectures have to support multiple mobile virtual network operators (MVNOs). They have also to host different types of these virtual operators. Virtualizing these architectures will allow the MVNOs to rapidly deploy their equipment. It will separate the management domain between them and the mobile host operator. It will also allow sharing resources and reducing the deployment cost. Motivated by these requirements, we propose some MVNO distributed architectures. First of all, we evaluate the physical and virtual deployment time, then we define the utility function of the equipment for the different types of MVNOs. The utility function evaluates the gain in deployment time for each type of MVNO. This function has to be maximized. Our study demonstrates that the data calls type is the best MVNO candidate for virtualization. This latter consistently yields the best overall utility across an important number of network equipment to be virtualized by varying the time required for software installation and the time spent to determine the physical position of the equipment.     

Crystal Structure–Ionic Conductivity Relationships in Doped Ceria Systems

In the past, it has been suggested that the maximum ionic conductivity is achieved in ceria, when doped with an acceptor cation that causes minimum distortion in the cubic fluorite crystal lattice. In the present work, this hypothesis is tested by measuring both the ionic conductivity and elastic lattice strain of 10 mol% trivalent cation-doped ceria systems at the same temperatures. A consistent set of ionic conductivity data is developed, where the samples are synthesized under similar experimental conditions. On comparing the grain ionic conductivity, Nd_0.10Ce_0.90O_2−δ exhibits the highest ionic conductivity among other doped ceria systems. The grain ionic conductivity is around 17% higher than that of Gd_0.10Ce_0.90O_2−δ at 500°C, in air. X-ray diffraction profiles are collected on the sintered powder of all the compositions, from room temperature to 600°C, in air. From the lattice expansion data at high temperatures, the minimal elastic strain due to the presence of dopant is observed in Dy_0.10Ce_0.90O_2−δ. Nd_0.10Ce_0.90O_2−δ exhibits larger elastic lattice strain than Dy_0.10Ce_0.90O_2−δ with better ionic conductivity at intermediate temperatures. Therefore, it is shown that the previously proposed crystal structure–ionic conductivity relationship based on minimum elastic strain is not sufficient to explain the ionic conductivity behavior in ceria-based system.