On the hardening effect of plasma-deposited coatings

We studied the influence of plasma-deposited titanium-nitride coatings on the characteristics of short-term static strength of the matrix material. In the process of deposition of these coatings, we observed an increase in the conventional yield limit and ultimate strength of the material accompanied by a decrease in the characteristics of plasticity. Institute of Problems of Strength, National Academy of Sciences of Ukraine, Kiev, Ukraine. Translated from Problemy Prochnosti, No. 6, pp. 123–126, November–December, 1999.     

Simulation of the stepped surface of a high-resolution X-ray diffractor

Three possible schemes of a high-resolution stepped X-ray diffractor have been analyzed, including those based on the steps of equal angular widths, the steps of equal heights (i.e., distances from the step edge to the beginning of the next step), and the symmetric steps (where a distance from the step edge to the focusing circumference is equal to the distance from the focusing circumference to the edge of the next step). It is shown that the first and the third schemes provide most stable characteristics.     

An approach for preventing the indexing of hijacked journal articles in scientific databases

Hijacked journals are cloned websites that resemble the homepages of legitimate journals, whose aim is to collect processing and publication fees from unwary authors. There is a growing recognition that the recent proliferation of these scam sites poses a threat to the integrity of the scientific process. This study presents an approach intended to prevent the indexing of papers published by hijacked journals in scientific databases by using classification algorithms. We will provide an overview of the problem, define key features of hijacked journals, and present a decision tree that can be used to detect hijacked publications.     

Hermetia illucens Larvae as a Living Bioreactor for Simultaneous Food by-Products Recycling and Useful Oil Production

The effects of feeds containing several food by-products on the fatty acid compositions of Hermetia illucens larvae were studied. Coconut, tomato, apple, and viscera by-products, as well as combinations of control feed containing carbohydrate-rich additives were assayed. Final live weight (mg) and daily growth coefficient (%/day) ranged from 41 and 0.548 (tomato) to 93 and 1.292 (coconut), respectively. Oils containing lauric acid were obtained from larvae-fed vegetable by-products, especially those fed feed containing apple, coconut, and tomato (65.3, 54.4 and 52.3% of total fatty acids, respectively). Feed containing apple and a 1:1 (w/w) mix of control feed and apple by-products yielded the highest proportion of fatty acids in the larvae (23.5 and 15.6 g fatty acids/100 g fresh larvae, respectively). The properties of biodiesel that could be produced from larvae fatty acids were calculated and the following values were obtained: cetane number (58.5–60.2), higher heating value (38.3–39.0 MJ·kg⁻¹), density (0.869–0.873 g·cm⁻³), and induction period, an index of oxidation stability (8.4–150 hours). Such values were within the ranges specified by the ASTM D6751 and Europe EN 14214:2008 standards, while values for cold filter plugging point (−9.6 to 2.8 °C) were adequate for biodiesels intended for use in temperate climates. However, values for kinematic viscosity (2.93–3.58 mm²·s⁻¹) were slightly below the requirements of EN 14214:2008 (3.5–5.0). Overall, larvae fed food by-products produced lauric acid-rich oils, and the calculated properties of the oils were largely suitable for biodiesel production.     

The leontief-ford dynamic optimization model under conditions of ecological equilibrium

The ecological-economical optimization problem based on the Leontief-Ford model is investigated. Necessary and sufficient conditions of the optimal solution are described for the discrete variant of the model. Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 73–79. March–April, 2000.     

On the Estimation of Softening of Ablating Heat-Shielding Coatings

A method of analytical estimation of softening of ablating heat-shielding coatings is considered. The softening is evaluated by the coefficient that describes the effect of variation in the modulus of elasticity with increasing temperature on the process of softening and takes into account the pattern of the temperature field determined from the character of the temperature dependence of the heat conductivity coefficient. An acceptable agreement of the calculated and experimental results under conditions of quasi-stationary ablation is shown.     

Dependence of the Structure of Sintered Boron Carbonitride on the Defect Level in the Starting BN Powder

We have carried out a comparative x-ray analysis of boron nitride powders with different degrees of ordering and sintered specimens of boron carbonitride based on such powders. We have established that an indicator of sintering activity for the boron carbonitride specimens is the rate of formation of the r-BN phase, the content of which depends on the degree of ordering of the starting BN powder. __________ Translated from Poroshkovaya Metallurgiya, Nos. 5–6(443), pp. 100–107, May–June, 2005.     

Electrical conductivity of nanostructured fluorite-like Sc<Subscript>4</Subscript>Ti<Subscript>3</Subscript>O<Subscript>12</Subscript>

Single-crystal and polycrystalline samples of Sc₄Ti₃O₁₂ have been shown to contain nanodomains (10–50 nm) with different degrees of ordering, coherent with the fluorite-like matrix. The oxygen-ion conductivity of this compound has been determined in the range 300–1000°C in air using impedance spectroscopy. The nanostructured single-crystal and polycrystalline samples are close in the activation energy for bulk conduction at both low and high temperatures: ?1.26 and 1.29 eV in the range 300–775°C, ?1.98 and 2.07 eV in the range 775–1000°C.     

On the theory of bubble domain motion in propagation circuits

The stability conditions for a bubble domain in the fields of magnetostatic traps are analyzed. For this purpose the quasi-stationary equations of bubble motion are derived which take into account field nonuniformity across the bubble diameter. The contribution of the Permalloy overlay is considered qualitatively. The conditions of static and dynamic stability of trapped bubbles are studied and the stability role in the operating margin development is analyzed.