Redox Equilibrium of Iron in Silicate Glasses

The effect of some additives on the equilibrium of valence forms of iron is investigated. It is demonstrated that tin and carbon more significantly than fluorine reduce iron. The redox potential of the glass matrix affects the equilibrium between difference valence forms of iron much less than additives correcting spectral characteristics of glass.     

Film Formation in Binary Sol-Gel Systems

The film-forming capacity of binary systems containing Sb₂O₃, SnO₂, CeO₂, Y₂O₃, Nd₂O₃, Bi₂O₃, V₂O₅, ZnO, CuO, CdO, and Al₂O₃ are investigated. The best film-formers are Sb₂O₃ and SnO₂, whereas ZnO, CuO, CdO, and Al₂O₃ cannot produce films of optical quality. The rest of considered oxides do not impair the clarity of coatings when their molding content is 20 – 50%. A proportional dependence is established between the refractive index and the reflection coefficient of a film and the refractive indexes of oxides making parts of this film, as well as between the concentration of deposited FFS, the film-forming capacity of oxides, and the film thickness.     

Passive-Based Walking Robot

In this article, we presented our passive-based biped Denise. Using only two foot contact switches as sensors and simple on/off pneumatic muscle action, it walks at 0.4 m/s and can handle floor disturbances up to 6 mm (leg length is 0.7 m). Its simplicity, efficiency, and die natural look of its motions make it a promising lead for the development of commercially viable humanoid robots. The aim of this article is to provide other researchers enough details so that they can reproduce the work or use it as a basis for future research.     

Solution-Processed n-Type Organic Field-Effect Transistors With High on /off Current Ratios Based on Fullerene Derivatives

Solution-processed n-type organic field-effect transistors (OFETs) based on the fullerene derivative {6}-1-(3-(2- thienylethoxycarbonyl)-propyl)-{5}-l-phenyl-[5,6]-C61 (TEPP) and phenyl-C61-butyric acid methyl ester (PCBM) in a multiring source/drain structure are reported. Devices with TEPP show high electron mobility up to 7.8 x 10^-2 cm²/Vs in the saturation regime for bottom-contact OFETs with Au S/D electrodes with a solution-processed fullerene derivative. The ON/OFF ratios reported in this letter, which are in the range of 10⁵ -10⁶, are among the highest values reported for such devices. This mobility is always higher compared to PCBM devices prepared in identical conditions. The mobility of TEPP and PCBM increased with increasing temperatures in the range of 100-300 K with activation energy of 78 and 113 meV, respectively, which suggests that the thermally activated hopping of electrons is dominant in TEPP.     

Metabolic-heat relation for aerobic yeast respiration and fermentation

A specially developed temperature control system on a laboratory scale fermenter enabled continuous measurement of the rate of heat production during undisturbed growth of microbial cultures. Apart from being correlated with oxygen uptake rate, the heat of fermentation was established as an additional indicator of metabolic activity. The ‘aerobic respiration’ energetic activity of Candida utilis, Candida lipolytica and Saccharomyces cerevisiae on different carbon substrates was investigated with cultures of the latter species being also studied under the ‘aerobic fermentation’ conditions induced by glucose catabolite repression.     

Neutron and capture γ-ray accumulation factors in engineering calculations of reactor shielding

Translated from Atomnaya Énergiya, Vol. 66, No. 5, pp. 321–324, May, 1989.     

Space asymptotic method for the study of neutron propagation

Space asymptotic theory is shown to be a suitable model for the study of pulsed experiments in neutron multiplying systems. After a short revisitation of the basic aspects of space asymptotic theory applied on the Laplace transformed one-group transport equation, the full solution is derived. It is shown how results are exact in representing localized pulse propagation in the first portion of the transient, until the boundary is reached by the neutron signal, since it propagates with a finite velocity. Approximate models are then derived starting from the exact formulation and the B_N method is used to account for anisotropy effects. Numerical results are presented for one-dimensional systems, discussing the physical phenomena and noting the distortions introduced by approximate models, which may then turn out to be inadequate for the simulation of realistic pulsed experiments situations.     

Rapid and comprehensive indicator for evaluation of performance of treatment processes and of river waters.

Naturally occurring UV active compounds, commonly present in almost all source waters, can be rapidly monitored by their ultraviolet absorbance at 260 nm (E260). Herein, the extent of correlation between the E260 and the removal efficiency of the hazardous contaminants, endocrine disrupters and dioxins, were investigated using various treatment and river source waters. The detection of various types of hazardous contaminants using sophisticated analytical methods, such as high resolution gas chromatography (HRGC)/high resolution mass spectrometry (HRMS) and high performance liquid chromatography (HPLC)/inductively coupled plasma (ICP)/mass spectrometry (MS), as well as various short-term bioassays, can require hours or even days for results to be obtained. The removal of the E260 correlated well with those of individual contaminants, such as endocrine disruptor chemicals and dioxins, with the various treatment processes employed. In the plots of the endocrine disrupters against the DOC/E260, a correlation was found with the endocrine activity of the Korean/Japanese river waters employed in this study.