Chemical activation of the SHS process in the Nb−C system

The phenomenon of chemical activation is investigated using combustion of the Nb–C system in the presence of an activating additive, namely, polytetrafluoroethylene, as an example. Regions of the parameters of the process are found where the interaction occurs by two different mechanisms. The characteristic features of the process are established and the role of the activating additive in each region is determined.Institute of Chemical Physics, Academy of Sciences of Armenia, Yerevan. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No.5, pp.590–593, November, 1993.     

Guaranteed search of a target object by an electromechanical system with minimal light power inputs

An optimal guaranteed control problem for electromechanical manipulator with the goal of finding an immovable or mobile target objects is considered. Unlike [1–6], as the optimality criterion, a functional taking into account power inputs of the light source on the gripper of the manipulator is taken. The sought object is assumed to be detected if it falls into the light circle with given illumination. The control algorithms of the gripper motion and corresponding laws of electric current variation in the light source circuit providing the detection of both immovable and mobile sought object in a guaranteed time for minimal light power inputs during the search are developed. The gain in light power inputs achieved for the proposed search algorithms is estimated.     

创造水经济系统发展有利条件的探讨

根据地区、年代和季节的不同,许多由水资源缺乏合理分配的复杂问题出现在水资源和水系统管理中.为创建水经济系统发展的有利条件,因此必需要开发和提供长期、计划合理的饮用水和生活用水系统,使其具有可维护性和高生产能力,要减少水的损失,提高水供应的持续时间,并且提升供水和水处理的质量.     

Electrochemical features of combustion-synthesized lithium cobaltate as cathode material for lithium ion battery

Lithium cobaltate (LiCoO₂) was produced by carbon combustion synthesis of oxide (CCSO) using carbon nanoparticles as a fuel. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm (specific surface 80 m²/g) gives rise to a self-propagating thermal wave with maximum temperatures of up to 900°C. The thermal front rapidly propagates through the mixture of solid reactants converting it to lithium cobaltate. XRD data suggest that the as-synthesized products were single phase. Carbon is not incorporated in the product and is evolved from the reaction zone as gaseous CO₂. Thermogravimetric analysis was used to identify the features of interaction in the LiNO₃-Co₃O₄-C system. The key features affecting the process-carbon pre-concentration in the reacting mixture and oxygen infiltration to the reaction zone-led to the formation of layered structure of LiCoO₂ and affected the particle sizes. The synthesized crystalline nanoparticles were nearly spherical, and their average particle diameters ranged between 60 and 200 nm.     

Features of combustion in the system niobium-carbon in the presence of an activating addition

Combustion processes are considered for stoichiometric mixtures of niobium with carbon with substitution of some of the carbon black by an activating addition, i.e. fluoroplastic. It is shown that in the presence of a small amouni (0.1–1.0 wt.%) of fluoroplastic the mixture acquires the capacity to burn without using any additional procedures.Erevan. Translated from Fizika Goreniya i Vzryva, Vol. 27, No. 6, pp. 72–77, November–December, 1991.     

Design and construction of accelerator signal electrodes

A method is given for making a design calculation of signal electrodes for fixed burst parameters and fixed overall dimensions of the field-free space in the accelerator vacuum chamber. Also the sensitivity may be determined when measuring either the intensity or the position of the center of gravity of the beam. A method is given for finding the engineering limitations placed on the construction of measuring apparatus. The results of the calculation made by this method are in good agreement with experiment.     

High-accuracy optoelectronic transducer for linear displacement based on a CCD and microelectronics

Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1990.     

Hot zones formation during regeneration of diesel particulate filters

A diesel particulate filter (DPF) is used to remove particulate matter (PM) from the diesel engine exhaust. The accumulated PM is periodically removed by combustion, which sometimes leads to excessive temperature excursions that melt the ceramic filter. This behavior cannot be explained by operation under stationary feed conditions. We propose that these temperature excursions are a dynamic effect following a rapid change in the driving mode while the DPF is being regenerated. Specifically, a rapid decrease in the exhaust temperature can lead to a counterintuitive large transient temperature rise above that which would exist under a higher stationary feed temperature. This unexpected behavior is similar to the well‐known wrong‐way behavior in packed‐bed reactors, even though the axial‐dependent flow through the filter in a DPF is rather different from the constant axial flow through a packed bed. We present simulations that provide insight about the dependence of the amplitude of this wrong‐way temperature rise on the filtration velocity, the PM loading, dimensions of the DPF, and the amplitude of the rapid temperature decrease and when it occurs after the start of the regeneration. The insight provided by these simulations will help develop operation and control protocols that circumvent or at least decrease the probability of the occurrence of the destructive melting of the DPF. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Universal Infrared Radiometer

The structure of a universal IR-radiometer sensitive in the wavelength range 0.4 to 20 μm is described in the paper. The device allows measurement of weak photoelectric signals, at the intensity levels considerably lower than the internal noise level of IR detectors. Both mechanical and electrical chopping of radiation is used. An original approach to design of some units is suggested. The small chopper is used on the optical axis of the device, allowing its easy targeting. The radiometer has a broad dynamic range of IR intensity measurements.