A General Reliable Quadratic Form: An Extension of Affine Arithmetic

In this article, a new extension of affine arithmetic is introduced. This technique is based on a quadratic form named general quadratic form. We focus here on the computation of reliable bounds of a function over a hypercube by using this new tool. Some properties of first quadratic functions and then polynomial ones are reported. In order to show the efficiency of such a method, ten polynomial global optimization problems are presented and solved by using an interval branch-and-bound based algorithm. The work of the first author was also supported by the Laboratoire de Mathématiques Appliquées CNRS–FRE 2570, Université de Pau et des Pays de l'Adour, France, and by the Laboratoire d'Electrotechnique et d'Electronique Industrielle CNRS–UMR5828, Group EM³, INPT–ENSEEIHT.     

Analysis of global and local extrema of regularizing functionals in the problem of the reconstruction of images observed through randomly inhomogeneous media

An approach to the reconstruction problem of undistorted images of objects observed through randomly inhomogeneous media is considered. The approach is based on the solution to the integral equation of the first kind (convolution equation) with an unknown kernel and inaccurately defined right-hand side. It is demonstrated that the procedure for the construction of an inverse operator needed for the solution is determined by the minimization of the nonlinear regularizing multiextremum functional, which takes into account the a priori data regarding the positive intensity distribution in the image of an object. The analysis of the structure of the multiextremum functional is presented. The estimates of the reconstructed images that correspond to the global and local extrema are studied. The results of a numerical experiment on the reconstruction of the optical image of an object observed through the turbulent atmosphere are presented.     

Pulse discharge characteristics of an insulating system typical of a nonlinear overvoltage limiter

Results of the studies of the discharge characteristics of insulating systems of high-voltage overvoltage limiters during lightning pulses are presented. For certain dimensions of the screen system of the overvoltage limiters, it is shown that the electric strength of their external insulation may be determined by the discharge voltages of the gap between the screen and the stack of voltage-dependent resistors. A semi-empiric technique for calculating the discharge voltages of the insulating systems of overvoltage limiters during lightning surge is developed.     

A study of the phase composition of iron-ore briquets to assess their behavior in a blast furnace

We study a mechanism for maintaining the strength of cement-bonded iron-oxide-bearing briquets when heated under reducing conditions. These briquets retain their strength when heated in a reducing atmosphere: up to 700–750°C, strength retention is due to the cement stone; strength retention under further heating is due to the continuous metal shell formed on the surface of the briquet as the iron oxide in the surface layer of the briquet is reduced to iron. Fabrication and usage of briquets of iron-ore concentrate can be recommended as a wash material for blast furnaces. Disperse materials containing SiO₂ and MgO should be added to the charge during fabrication of the briquets in order to improve the washing properties of briquet slag.     

Enhancement of the luminescence yield of Er3+ ions at λ=1.54μmm in ZBLAN glass additionally doped with Eu3+ and Tb3+ and pumped in the range λ=0.975 μm

In fluorozirconate glasses the luminescence yield of Er ₂ ³⁺ ions on the ⁴ I _13/2–⁴ I _15/2 lasing transition was increased more than tenfold by additional doping with Yb³⁺ and Tb³⁺ ions. Pis’ma Zh. Tekh. Fiz. 24, 81–85 (May 12, 1998)     

Structure formation in production of yttrium-silicate materials by the sol-gel method

Materials made from yttrium silicates were synthesized by the sol-gel method. The effect of the amount of yttrium oxide, which varied from 10 to 50% (molar content), and the water:alcoholate molar ratio was investigated. Structure formation and the character of crystallization of gels in heat treatment in the 650–1300°C range were investigated. __________ Translated from Steklo i Keramika, No. 1, pp. 3–6, January, 2007.     

Formation of carbon nanofibers via carbon monoxide disproportionation

Experimental results suggesting that carbon nanofibers are formed from amorphous carbon released at several compact active sites are reported. It was shown that the sites in question are catalyst crystal lattice defects formed at the crystallite contact boundaries.     

Chemical and Physical Signals Mediating Conspecific and Heterospecific Aggregation Behavior of First Instar Stink Bugs

We investigated cues that mediate the aggregation behavior of immature pentatomid bugs by using nymphs of six different pentatomid bug species (Nezara viridula, Acrosternum hilare, Chlorochroa ligata, Chlorochroa sayi, Thyanta pallidovirens, and Euschistus conspersus). When first instars of any two species were put together in a Petri dish, they readily formed heterospecific aggregations similar to their natural conspecific aggregations. The chemical profiles of first and second instar nymphs of each species were determined by solvent extraction with pentane, followed by GC-MS analysis. Immature bugs of the different species had some compounds in common, and some that were more species specific. Within a species, there were distinct differences in the profiles of compounds extracted from first and second instars. Bugs did not aggregate around untreated polysulfone beads (1 mm diam) that were glued together in groups approximating bug egg masses, suggesting that tactile cues alone were insufficient to induce aggregation. Furthermore, when tested over a range of doses, groups of polysulfone beads treated with crude whole-body extracts of bugs did not induce or maintain aggregations. However, first instar N. viridula nymphs did respond to beads treated with two of the three major components of bug extracts. 4-Oxo-(E)-2-decenal induced significant aggregations at two doses, whereas tridecane, the major component in extracts from all six species, did not, and (E)-2-decenal was repellent. The repellence of (E)-2-decenal may explain why we and previous researchers were unable to induce aggregations of first instar N. viridula using whole-body extracts.     

The difficultly extractable lipides of cottonseed meats,their composition and effect on the refining characteristics of the crude oils

Summary and Conclusions Crude lipides fractions were produced from raw, tempered, and cooked meats from two lots of cottonseed by a series of successive stepwise extractions, designed to obtain fractional portions of the total lipides in the order of the difficulty of their extraction. The proximate composition of the crude lipides fractions was determined. It was found that the composition of successive lipides fractions varied with the degree of exhaustiveness of extraction. The fractions obtained by more exhaustive extraction contained greater amounts of undesirable non-neutral oil material and lesser amounts of desirable neutral oil. It was also established that the method used in preparing meats for extraction was of paramount importance in its effect on the composition of the crude lipides obtained. The crude lipides fractions from raw and tempered meats contained large amounts of impurities while the crude lipides fractions similarly obtained from cooked meats were relatively low in impurities. Crude oils equivalent to varying degrees of total lipides extraction were reconstituted from the crude lipides fractions and evaluated for refining characteristics. The impurities content of the reconstituted oils varied as the degree of total lipides extraction and increases in the impurities content of the oils were generally reflected in disproportionate increases in refining losses and/or refined oil color. The oils obtained from the cooked meats at all degrees of extraction were outstandingly low in refining losses as compared to the oils from the raw and the tempered meats. Presented in two parts at the spring meeting, American Oil Chemists’ Society, New Orleans. La., Apr. 18–20, 1955, and at the fall meeting, Philadelphia, Pa., Oct. 10–12, 1995. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Estimators of the reliability index of a nonrepairable one-shot item by small statistical samples

The evaluation of the reliability indices of a nonrepairable one-shot item based on small statistical samples using a priori information has been presented. The novelty of the obtained results consists of formulating cases when the F test should be used as well as the t test, and the proposed simple method for determining the lower limit of the complex reliability index.