COMPARATIVE ANALYSIS OF ENERGY ACCUMULATION SYSTEMS AND DETERMINATION OF OPTIMAL APPLICATION AREAS FOR MODERN SUPER FLYWHEELS

The paper presents a review and comparative analysis of late years native and foreign literature on various energy storage devices: state of the art designs, application experience in various technical fields. Comparative characteristics of energy storage devices are formulated: efficiency, quality and stability. Typical characteristics are shown for such devices as electrochemical batteries, super capacitors, pumped hydroelectric storage, power systems based on compressed air and superconducting magnetic energy storage systems. The advantages and prospects of high-speed super flywheels as means of energy accumulation in the form of rotational kinetic energy are shown. High output power of a super flywheels energy storage system gives the possibility to use it as a buffer source of peak power. It is shown that super flywheels have great life cycle (over 20 years) and are environmental. A distinctive feature of these energy storage devices is their good scalability. It is demonstrated that super flywheels are especially effective in hybrid power systems that operate in a charge/discharge mode, and are used particularly in electric vehicles. The most important factors for space applications of the super flywheels are their modularity, high efficiency, no mechanical friction and long operating time without maintenance. Quick response to network disturbances and high power output can be used to maintain the desired power quality and overall network stability along with fulfilling energy accumulation needs

Influence of Shear-Thinning Rheology on the Mixing Dynamics in Taylor-Couette Flow

Non‐Newtonian rheology can have a significant effect on mixing efficiency, which remains poorly understood. The effect of shear‐thinning rheology in a Taylor‐Couette reactor is studied using a combination of particle image velocimetry and flow visualization. Shear‐thinning is found to alter the critical Reynolds numbers for the formation of Taylor vortices and the higher‐order wavy instability, and is associated with an increase in the axial wavelength. Strong shear‐thinning and weak viscoelasticity can also lead to sudden transitions in wavelength as the Reynolds number is varied. Finally, it is shown that shear‐thinning causes an increase in the mixing time within vortices, due to a reduction in their circulation, but enhances the axial dispersion of fluid in the reactor

Nowe podejście do modelowania błędów geometrycznych precyzyjnych maszyn technologicznych

This paper presents a new approach to modeling geometric errors in machine tools with linear rolling guideways. Modeling was performed using a finite element method. The results of the modeling were a visualization of deformations of a virtual milling machine with a cross table and with known characteristics of guide geometric errors. The simulation results show that the machine table is subject to a complex state of strain. This implies that the Abbe error during milling machine measurements can assume values dependent on the location of metrological device elements on the machine table. The calculation results were verified experimentally using real milling machines. The predictions of the computer simulation were confirmed.W artykule przedstawiono nowe podejście do modelowania błędów geometrycznych obrabiarek wyposażonych w liniowe toczne połączenia prowadnicowe. Modelowanie przeprowadzono z użyciem metody elementów skończonych. Efektem modelowania jest wizualizacja odkształceń frezarki poziomej ze stołem krzyżowym, która ma znane charakterystyki błędów geometrycznych połączeń prowadnicowych. Analiza wyników procesu symulacji wykazała, że stół takiej obrabiarki podlega złożonemu stanowi odkształcenia. Ma to istotne znaczenie praktyczne, ponieważ podczas wykonywania pomiarów błędów geometrycznych obrabiarek – błąd Abbego może przyjmować różne wartości w zależności od usytuowania przyrządów pomiarowych na stole frezarki. Wyniki obliczeń zweryfikowano doświadczalnie na rzeczywistych frezarkach. Potwierdzono przewidywania symulacji komputerowej

Methods of testing of technological motion errors on precision CNC turning centers

Artykuł prezentuje wyniki części prac, których celem była ocena dokładności technologicznej precyzyjnych tokarek i centrów tokarskich CNC. Przedstawiono przykłady metod badań dokładności nastawianych ruchów technologicznych (posuwowych, obrotowych, interpolowanych), na podstawie których można ocenić wpływ błędów tych ruchów na dokładność różnych rodzajów obróbki wykorzystujących złożenie ruchów posuwowych, posuwowych i obrotowych, synchronizacji ruchów. Omówiono metody, dzięki którym można diagnozować przyczyny powstawania błędów tego rodzaju obróbki, a mianowicie dokładność nastawionego ruchu. Dokładność ta nie zależy tylko od dokładności geometrycznej, pozycjonowania, ale także od możliwości i ustawionych parametrów działania układów regulacji. Opisano przykłady metod badań: - dokładności i równomierności nastawionej prędkości obrotowej wrzecion - błędów odzwierciedlania zadanej trajektorii ruchów interpolowanych - błędnych ruchów wirującego przedmiotu zamocowanego w uchwycie. Przedstawiono przykłady diagnostyki błędów ruchów technologicznych i ich przyczyn na podstawie opisanych metod badań.This article presents part of research with the object of evaluation of technological accuracy of precision lathes and CNC turning centers. Presented are examples of methods of accuracy testing of set technological motions (linear, rotary, interpolated), on the basis of which one can evaluate the influence of errors of these motions on accuracy of various types of machining that are utilizing synchronization of linear, rotary motions. Discussed are methods which make it possible to diagnosis the causes of occurring errors of this kind of machining in which main causes of errors can be the accuracy of set motion. This accuracy can originate not only from geometrical accuracy of positioning, but also from capabilities and set parameters of control systems. Described are the examples of testing methods of: - accuracy and steadiness of set rotational speed of spindles, - errors of performing of set trajectory of interpolated motions, - error motions of rotating workpiece clamped in chuck. Presented are examples of diagnosis of technological motion errors and their causes as based on described testing methods

Diagnostics of machine tool spindles based on rotating axes error motions

Opisano metodykę pomiarów błędnych ruchów wirujących osi. Przedstawiono możliwości wykorzystania tej metodyki do oceny i diagnostyki pracy wrzecion obrabiarek w zakresie dokładności geometrycznej łożysk i oprawek narzędzi, przemieszczeń wirującej osi, przemieszczeń drgań iprzemieszczeń temperaturowych końcówki narzędzia oraz wykrywania nieprawidłowości pracy wrzecion. Przedstawiono przykładowe wyniki diagnostyki elektrowrzecion obrabiarek CNC i wykrytych błędów będących przyczyną nieprawidłowej obróbki (błędów kształtu, podwyższonej chropowatości, łamania i szybkiego zużycia ostrzy płytek skrawających)We describe the measurement methodology of rotating axes error motions. We present the possibility of utilizing this methodology to assess and diagnose machine tool spindles in scope of geometrical accuracy of bearings and toolholders, displacement of rotating axis, displacement of vibrations, thermal deformation of spindle nose and to detect a malfunction in spindle operation. We present example results of CNC machine tool mo- tor spindle diagnosis and detected errors that the source of machining abnormality (shape errors, breakage or increased wear of cutting inserts, increased roughness)

Molecular modelling techniques in environmental research

Over the last few decades significant increase in computational methods (in silico) was annotated. Novel methods have been developed and applied for hypothesis improvement and testing in regions of industrial, pharmaceutical and environmental research. The term in silico methods include variety of approaches. Considerable attention has been attracted to databases, data analysis tools, quantitative structure-activity relationships (QSAR), pharmacophore models, molecular docking and dynamics, pharmacokinetics and other molecular modelling techniques. In silico methods are often accompanied by experimental data, both to create the model and to test it. Such models are frequently used in the discovery and optimization of novel molecules with expected affinity to a target, the estimation of absorption, distribution, metabolism, excretion and toxicity properties as well as physicochemical characterization. The review summarizes briefly the applications of most common molecular modelling techniques and evaluates their application in environmental research. Additionally, this study considers computer aided methods as potential and complex tools that may serve as valuable partnership with wet-lab experiments and may provide a rational aid to minimize the cost and time of research

Molecular modelling techniques in environmental research

Over the last few decades significant increase in computational methods (in silico) was annotated. Novel methods have been developed and applied for hypothesis improvement and testing in regions of industrial, pharmaceutical and environmental research. The term in silico methods include variety of approaches. Considerable attention has been attracted to databases, data analysis tools, quantitative structure-activity relationships (QSAR), pharmacophore models, molecular docking and dynamics, pharmacokinetics and other molecular modelling techniques. In silico methods are often accompanied by experimental data, both to create the model and to test it. Such models are frequently used in the discovery and optimization of novel molecules with expected affinity to a target, the estimation of absorption, distribution, metabolism, excretion and toxicity properties as well as physicochemical characterization. The review summarizes briefly the applications of most common molecular modelling techniques and evaluates their application in environmental research. Additionally, this study considers computer aided methods as potential and complex tools that may serve as valuable partnership with wet-lab experiments and may provide a rational aid to minimize the cost and time of research

Hyperthermic intraperitoneal chemotherapy (HIPEC) in combined treatment of locally advanced and intraperitonealy disseminated gastric cancer: A retrospective cooperative Central-Eastern European study

Background and Objectives: Clinical experience in Western Europe suggests that cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are promising methods in the management of gastric cancer (GC) with peritoneal metastases. However, there are almost no data on such treatment results in patient from Central‐Eastern European population. Methods: A retrospective cooperative study was performed at 6 Central‐Eastern European HIPEC centers. HIPEC was used in 117 patients for the following indications: treatment of GC with limited overt peritoneal metastases (n = 70), adjuvant setting after radical gastrectomy (n = 37) and palliative approach for elimination of severe ascites without gastrectomy (n = 10). Results: Postoperative morbidity and mortality rates were 29.1% and 5.1%, respectively. Median overall survival in the groups with therapeutic, adjuvant, and palliative indications was 12.6, 34, and 3.5 months. The only long‐term survivors occurred in the group with peritoneal cancer index (PCI) of 0‐6 points without survival difference in groups with PCI 7‐12 vs PCI 13 or more points. Conclusions: GC patients with limited peritoneal metastases can benefit from CRS + HIPEC. Hyperthermic intraperitoneal chemotherapy could be an effective method of adjuvant treatment of GC with a high risk of intraperitoneal progression. No long‐term survival may be expected after palliative approach to HIPEC