ЕКОНОМІЯ ЕЛЕКТРИЧНОЇ ЕНЕРГІЇ ПРИ РЕМОНТІ ДОПОМІЖНИХ МАШИН ЕЛЕКТРОВОЗІВ ПОСТІЙНОГО СТРУМУ

На цей час зростання вартості електричної енергії для підприємств залізниці значно впливає на вартість ремонту електровозів. Підприємства постійно впроваджують нові технології та пристрої, які дозволяють виконати деяку економію енергетичних ресурсів. Це і нові системи освітлення цехів, заміна електромашинних перетворювачів в стендах взаємного навантаження на статичні, в основі яких лежить сучасна напівпровідникова елементна база та ін. Щодо енергозбереження при випробуваннях тягових електричних двигунів постійного струму, то в цьому напрямку досягнуті значні результати

Структура сварных соединений наноструктурированного титанового сплава ВТ6, полученных при электронно-лучевой сварке

The paper presents the results of structure studies the properties of welded joints, produced by electron beam welding of titanium alloy VT6 in nanostructured condition. Revealed three characteristic zones in the area of the weld: zone of the base metal, heat affected zone and the zone of molten metal. It is established that the boundaries between these zones are diffuse

Boosting histograms of oriented gradients for human detection

Presentado al 2nd Computer Vision: Advances in Research & Development celebrado en 2007 en Bellaterra (Spain).In this paper we propose a human detection framework based on an enhanced version of Histogram of Oriented Gradients (HOG) features. These feature descriptors are computed with the help of a precalculated histogram of square blocks. This novel method outperforms the integral of oriented histograms allowing the calculation of a single feature four times faster. Using Adaboost for HOG feature selection and Support Vector Machine as weak classifier, we build up a fast human classifier with an excellent detection rate.This work was supported by the project 'Integration of robust perception, learning, and navigation systems in mobile robotics' (J-0929).This work is supported by EC grants IST-027110 for the HERMES project and IST-045547 for the VIDI-video project, and by the Spanish MEC under projects TIN2006-14606 and DPI-2004-5414. Jordi Gonzàlez also acknowledges the support of a Juan de la Cierva Postdoctoral fellowship from the Spanish MEC.Peer Reviewe

Перераспределение направления трещин гидравлического разрыва пласта с помощью оптимизации системы поддержания пластового давления

В данной статье описывается технология для контроля направления распространения трещин при проведении гидравлического разрыва пласта. С этой целью был проведен анализ уже имеющихся технологий. Представлено собственное решение для перераспределения направления трещины с помощью оптимизации системы поддержания пластового давления

Experimental and numerical investigation of the hydrodynamics of microfiltration processes using a multi-scale approach

Submerged membrane bioreactor (MBR) processes for treating municipal or industrial wastewater are one of the most promising applications of microfiltration membranes. Previous studies were spread over various fields of research including water science, microbiology, chemical engineering, material science and process control. All of the above research societies contributed comprehensively to a further improvement of the technology. Nevertheless, it is known that higher operational expenses compared to conventional water treatment strategies weaken the competitiveness of MBRs. More precisely, recent energy efficiency analyses identified the coarse bubble aeration of the membrane unit to consume the biggest proportion of the overall energy input. Therefore, hydrodynamic conditions in submerged microfiltration processes were investigated experimentally and numerically on three different scales in the framework of this study. The overall objective was to evaluate the impact of operating parameters, feed characteristics and module design features on the efficiency of air bubbling to control cake layer formation. On a micro-scale, local phenomena such as permeate flow, particle deposition and cake removal were non-invasively visualised with nuclear magnetic resonance (NMR) imaging. Complementary filtration experiments were conducted by applying a number of test facilities equipped with single hollow-fibres (meso-scale) or single hollow-fibre bundles (macro-scale) in different modes of operation. The bubble-induced fibre movement as a key parameter affecting the overall process performance was tracked with a direct observation (DO) technique (meso-scale). A macroscopic computational fluid dynamics (CFD) approach based on X-ray computer tomography (CT) scans and calibrated with numerical pressure loss correlations was established. The investigations have shown the impact of lumen-side pressure losses on the distribution of local permeate flux. Cake formation appeared to be heterogeneous, with thicker cakes close to the point of permeate extraction. The cake growth was in good agreement with the fouling rate dTMP/dt as a function of permeate flux, solids concentration and aeration conditions. Cake layer removal was enhanced with an increase in net aeration rate, bubble-induced fibre movement and background circulation flow. Interestingly, a higher aeration frequency for the same net aeration rate and an optimal gross aeration rate were observed, which outlines potentials for reducing aeration requirements. Fibre motion was more intensive for higher aeration rates, but insensitive to packing density variations. The CFD results were indicating a clear impact of fibre arrangement, superficial inlet velocity and solids concentration on the local cross-flow velocity and turbulence intensity. A well-defined slug flow was observed before the Taylor bubble penetrates into the porous medium. Moving forward, different module configurations will be evaluated with CFD, thus providing insights into the complex multi-phase flow pattern which are not accessible with experimental observation techniques