Transients in a circulating fluidized bed boiler

Transients in a circulating fluidized bed boiler firing biomass are considered. An attempt is made to describe transients with the use of concepts applied in the automatic control theory. The parameters calculated from an analysis of unsteady heat balance equations are compared with the experimental data obtained in the 12-MW boiler of the Chalmers University of Technology. It is demonstrated that these equations describe the transient modes of operation with good accuracy. Dependences for calculating the time constants of unsteady processes are obtained. © 2013 Pleiades Publishing, Inc

The Experimental WSN Network for Underground Monitoring H2 Abundance in the Mine Atmosphere Karnasurt Mine Lovozero Layered Alkaline Intrusion

We have developed specialized equipment based on mini-MDM hydrogen sensors and the WSN telecommunication technology for long-term monitoring of hydrogen content in the environment. Unlike existing methods, the developed equipment makes it possible to carry out measurements directly in the explosion zone with high discreteness in time. This equipment was tested at a large rare-earth deposit of the Lovozero Alkaline Pluton Karnasurt in the underground mining tunnel. We observed a short time very high concentration of hydrogen in the atmosphere (more than 3 orders of normal atmosphere concentration). This discovery is very important because at the time of the explosion one can create abnormally high concentrations of explosive mixtures of hydrocarbon gases that can lead to accidents. The high resolving power of the measurement equipment makes it possible to determine the shape of the anomaly hydrogen of such a concentration and to calculate the volumes of hydrogen released from the rocks, at first time in the practice. The shape of the anomaly usually consists of 2-3 additional peaks of the shape - "dragon-head-like peak". We make an first attempt is made to explain this form of anomaly in the article. The aim of the work in the estimation hydrogen emission in mining ore deposit rare earth elements

On the integral cohomology of smooth toric varieties

Let $X_\Sigma$ be a smooth, not necessarily compact toric variety. We show that a certain complex, defined in terms of the fan $\Sigma$, computes the integral cohomology of $X_\Sigma$, including the module structure over the homology of the torus. In some cases we can also give the product. As a corollary we obtain that the cycle map from Chow groups to integral Borel-Moore homology is split injective for smooth toric varieties. Another result is that the differential algebra of singular cochains on the Borel construction of $X_\Sigma$ is formal.Comment: 10 page

Influence of a binder on the electrochemical behaviour of Si/RGO composite as negative electrode material for Li-ion batteries

Received: 02.12.2020. Accepted: 21.12.2020. Published:30.12.2020.A composite consisting of silicon nanoparticles and reduced graphene oxide nanosheets (Si/RGO) was studied as a promising material for the negative electrode of lithium-ion batteries. Commonly used polyvinylidene fluoride (PVdF) and carboxymethyl cellulose (CMC) served as a binder. To reveal the influence of the binder on the electrochemical behaviour of the Si/RGO composite, binder-free electrodes were also prepared and examined. Anode half-cells with composites comprising CMC as a binder demonstrated the best properties: capacity over 1200 mAh·g–1, excellent cycling performance and good rate capability up to 1.0C.This work was performed with financial support from the Ministry of Science and Higher Education of Russian Federation, project ID RFMEFI60419X0235

HEAT EXCHANGER FOR COOLING STEAM-GAS MIXTURE

FIELD: power engineering.SUBSTANCE: heat exchanger comprises pipes with spiral-ring fins. The fins are provided with longitudinal slots. The pipes in the heat exchanger are arranged vertically.EFFECT: enhanced efficiency.3 dwg.Изобретение предназначено для применения в энергетических и отопительных котлах, сжигающих газообразное топливо. Теплообменник для охлаждения парогазовой смеси состоит из труб со спирально-кольцевыми ребрами, причем вдоль оси труб во всех ребрах выполнены продольные прорези, а трубы в теплообменнике расположены вертикально. Заявленное изобретение позволяет получить дополнительную теплоту при глубоком охлаждении продуктов сгорания природного газа за счет конденсации содержащегося в них водяного пара, получить обессоленную воду из продуктов сгорания (около 1 литра на 1 м3 сожженного газа), которая после деаэрации может быть использована для питания паровых котлов или других целей, получить водяной пар, остающийся в продуктах сгорания, находящийся в перегретом (не насыщенном) состоянии, что исключает его конденсацию на внутренних поверхностях теплоизолированных газоходов и дымовых труб. 5 ил