Preload Optimization: A High Efficiency Design Solution for Grinding Machines Main Spindles

2009 ◽  
pp. 74-74-11 ◽  
Author(s):  
GD Hagiu ◽  
MD Gafiţanu
Keyword(s):  
High Efficiency ◽  
Design Solution ◽  
Grinding Machines

scholarly journals High-voltage DC converter for solar power station

2020 ◽  
Vol 11 (4) ◽  
pp. 2135
Author(s):  
Mohamed Qawaqzeh ◽  
Roman Zaitsev ◽  
Oleksandr Miroshnyk ◽  
Mykhailo Kirichenko ◽  
Dmytro Danylchenko ◽  
...  
Keyword(s):  
High Efficiency ◽  
Electrical Energy ◽  
Design Solution ◽  
Maximum Power Point ◽  
Solar Concentrators ◽  
Boost Converters ◽  
Photovoltaic Modules ◽  
Wide Range ◽  
Simulation Based ◽  
Power Point

In the article the circuit design solution of DC-DC regulated resonant converter has been proposed for using with hybrid photovoltaic modules which has cooling equipment and solar concentrators in order to maximize electric power generating by such module. By using computer simulation based on multiple iterations algorithm we significantly increase the accuracy of determining the resonance circuit optimal parameters for build up DC–DC converters to work in a wide range of electric powers. Based on optimal values of the resonance LLC scheme parameters, achived by numerical calculation it can be show high values of electrical energy transformation efficiency for photovoltaic energy station equipped with high efficiency hybrid photovoltaic modules.  Implementation of microprocessor-based control into design of DC–DC back-boost converters create a new possibility to build control algorithms for increase reliability and conversion efficiency, rapid and precision stabilization of maximum power point, implementation network monitoring of photovoltaic modules, converters itself and the whole photovoltaic station parameters.

scholarly journals ОХОЛОДЖЕННЯ НАДДУВНОГО ПОВІТРЯ ГОЛОВНОГО СУДНОВОГО ДВИГУНА АБСОРБЦІЙНОЮ БРОМИСТОЛІТІЄВОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ЕКВАТОРІАЛЬНИХ ШИРОТАХ

2020 ◽  
pp. 30-35
Author(s):  
Андрій Миколайович Радченко ◽  
Дмитро Вікторович Коновалов ◽  
Іван Володимирович Калініченко ◽  
Чен Нінь ◽  
Хан Баочен
Keyword(s):  
High Efficiency ◽  
Cold Water ◽  
Waste Heat ◽  
Cooling System ◽  
Lithium Bromide ◽  
Design Solution ◽  
Intermediate Water ◽  
Absorption Chiller ◽  
Low Speed ◽  
Speed Engine

The efficiency of cooling the scavenge air of the main low-speed engine of the transport vessel during operation in the equatorial tropical latitudes is analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures and temperatures of seawater. The cooling of the scavenge air with an absorption lithium bromide chiller by transforming the scavenge air heat into the cold was investigated. With this, the potentially possible minimum temperature of the cooled air was determined considering the temperature of the cold water (coolant) from the absorption lithium bromide chiller and the temperature differences in the heat exchangers of the intermediate water circuit of cooling. Absorption lithium bromide chillers are characterized by high efficiency of transformation of waste heat into cold - high coefficients of performance. Circuit-design solution of three-stage cooling system of scavenging air of ship's main engine - in high-temperature (cogeneration) stage using the extracted heat of scavenging air to get cold with absorption chiller and traditional stage for cooling scavenge air by seawater and low-temperature cooling stage by absorption chiller. The effect of deeper cooling of the scavenge air was determined in comparison with the cooling of the scavenge air with seawater, taking into account the changing climatic conditions during the route of the vessel. It is shown that due to the high efficiency of heat transformation in absorption chillers (high coefficients of performance 0.7…0.8), there is a significant amount of excess heat of scavenging air over the heat required to cool it to 22 °C, which reaches almost half of the available scavenge air heat on the Shanghai-Singapore-Shanghai route. This reveals the possibility of additional cooling the inlet of the turbocharger of the engine with the achieving almost double fuel economy due to the cooling of all cycle air of the low-speed engine, including the air at the inlet.

scholarly journals Design of Grinding Machine Spindle

2018 ◽  
Vol 1 (1) ◽  
pp. 69-75
Author(s):  
Lukas Rudolf ◽  
Jiri Fries ◽  
Oldrich Ucen ◽  
Tomas Kubin ◽  
Lukas Kudrna
Keyword(s):  
Design Patterns ◽  
Design Theory ◽  
Design Solution ◽  
Position Change ◽  
Gravity Forces ◽  
Machine Spindle ◽  
Grinding Machines ◽  
Grinding Machine ◽  
External Forces

Abstract When grinding high demands are usually placed on the geometrical tolerances of the workpiece surface. For this reason, the spindles of the grinding machines are normally designed with requirements for a minimum position change of the grinding disks due to external forces and bending moments. The design theory of these spindles is relatively well elaborated, as it represents the most frequently used solution in practice. However, there are also cases where it is necessary to grind some hard-to-reach areas, using a great ejection of the spindle. In these cases, it is necessary to reassess the required geometrical tolerances with regard to its necessity to comply with the minimal changes in the position of the grinding discs due to the great ejection. Where it is necessary to maintain high geometrical tolerances, it is necessary to ensure a greater rigidity of the spindle. This rigidity is usually improved by increasing its diameter. By doing this we also increase the weight of the spindle that is heavily ejected, and thus its deformation can occur due to gravity forces. That is why it is necessary to analyse the deflection of the spindle depending on its ejection in the course of its design. In the case we increase the diameter of the grinder spindle the possible applicable grinding disc diameter decreases, due to the growing size of its housing. Any grinding of hard-to-reach surfaces is therefore done in particular to improve the quality of the surface with low requirements on the geometrical tolerances. This article deals with the design patterns for a spindle used in axial grinding for inner rotating surfaces. The article contains a spindle design solution and an analysis of its deflections, depending on its ejection, and the size of the passive forces.

scholarly journals Trends and development prospects of manual pneumatic grinding machines

2021 ◽  
pp. 42-47
Author(s):  
Ю.П. Кузнецов ◽  
В.Л. Химич ◽  
С.Н. Хрунков ◽  
А.Б. Чуваков ◽  
Р.А. Погодин
Keyword(s):  
High Efficiency ◽  
Cutting Tool ◽  
Design Analysis ◽  
Specific Power ◽  
Multi Stage ◽  
Long Time ◽  
Grinding Machines ◽  
Grinding Machine ◽  
Development Prospects ◽  
Common Action

В работе представлен анализ результатов эволюции параметров ручных пневматических шлифовальных машин на протяжении значительного интервала времени. Показаны достижения ведущих мировых производителей и выбраны три основных параметра, характеризующие возможности шлифовальных машин. Выявлены тенденции изменения удельной мощности и удельного расхода машин. Проведен сравнительный анализ перспектив развития машин с ротационным и турбинным приводом. Рассмотрена проблема совместной работы режущего инструмента и шлифовальной машины. Выявлена недостаточная быстроходность ручных пневматических шлифовальных машин с ротационным типом привода. Сделан вывод о большей перспективности применения многоступенчатых турбин в качестве привода шлифовальных машин. Представлен анализ компоновочных схем машин с турбинным приводом мировых производителей. Обоснована новая высокоэффективная конструктивная схема радиальных многоступенчатых турбин для привода пневматических шлифовальных машин. Показаны преимущества предложенной схемы, определены пути преодоления технологических барьеров при ее реализации. The paper suggests the results of analysis the parameters evolution of manual pneumatic grinding machines for a long time. The achievements of the world's leading manufacturers are shown and three main parameters that define the performance of grinding machines are selected. Trends in the specific power and specific air consumption of the machines are opened. An analysis of the development prospects for rotary and turbine machines is carried out. The problem of common action of a cutting tool and a grinding machine is considered. The insufficient speed of rotary manual pneumatic grinding machines is shown. It is determined that multi-stage turbines are most preferable for grinding machines. The design analysis of turbine machines of world manufacturers is presented. A new high-efficiency design of radial multi-stage turbines for driving pneumatic grinding machines is founded. The advantages of the new design are shown. The ways of overcoming technological challenges in the new design implementation are determined.

scholarly journals ОХОЛОДЖЕННЯ НАДДУВНОГО ПОВІТРЯ ГОЛОВНОГО СУДНОВОГО ДВИГУНА ЕЖЕКТОРНОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ЕКВАТОРІАЛЬНИХ ШИРОТАХ

2020 ◽  
pp. 24-29
Author(s):  
Микола Іванович Радченко ◽  
Дмитро Вікторович Коновалов ◽  
Чжан Цян ◽  
Лю Шаоцзюнь ◽  
Луо Зевей ◽  
...  
Keyword(s):  
Minimum Temperature ◽  
High Efficiency ◽  
Cooling System ◽  
Cooling Capacity ◽  
Climatic Conditions ◽  
Design Solution ◽  
Intermediate Water ◽  
Transport Vessel ◽  
Tropical Climates ◽  
Heat Deficit

The efficiency of cooling the scavenge air of the main low-speed engine of the transport vessel during operation in the equatorial tropical latitudes is analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures and temperatures of seawater. The cooling of the s scavenge air with a refrigerant ejector chiller was investigated by transforming the scavenge air heat into the cold. With this, the potentially possible minimum temperature of the cooled air was determined considering the boiling temperature of the refrigerant and the temperature differences in the heat exchangers of the intermediate water cooling circuit. Refrigerant ejector chiller is used as the most simple and reliable in design. However, the efficiency of converting the heat to cold by ejector chillers is low: their coefficients of performance are approximately 0.3. Circuit-design solution of three-stage cooling system of scavenging air of ship's main engine - in high-temperature (cogeneration) stage using the extracted heat of scavenging air to get cold with ejector chiller and traditional stage for cooling scavenge air by seawater and low-temperature cooling stage by ejector chiller. The effect of deeper cooling of the scavenge air was determined in comparison with the cooling of the scavenge air with seawater, taking into account the changing climatic conditions during the route of the vessel. It is shown that because of the insufficiently high efficiency of transformation of the scavenge air heat by the ejector chiller (low coefficients of performance) the obtained cooling capacity is not sufficient to cool the scavenge air to a potentially possible minimum temperature of 22 °C when operating the ship engine in tropical climates. However, the heat deficit is relatively small and can be covered by the use of additional exhaust gas heat.

scholarly journals ОХОЛОДЖЕННЯ ПОВІТРЯ НА ВХОДІ МАЛООБЕРТОВОГО ДВИГУНА ЕЖЕКТОРНОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ ПРИ ЕКСПЛУАТАЦІЇ СУДНА В ТРОПІЧНИХ УМОВАХ

2020 ◽  
pp. 17-21
Author(s):  
Роман Миколайович Радченко ◽  
Максим Андрійович Пирисунько ◽  
Нiн Чен ◽  
Баочен Хан
Keyword(s):  
High Efficiency ◽  
Waste Heat ◽  
Cooling Water ◽  
Climatic Conditions ◽  
Design Solution ◽  
Air Cooling ◽  
Low Speed ◽  
Exhaust Gases ◽  
Main Engine ◽  
Speed Engine

The efficiency of air cooling at the inlet of the main low-speed engine turbocharger of a transport vessel during operation in tropical climatic conditions on the Shanghai-Singapore-Shanghai route was analyzed. A feature of the tropical climate is the high relative humidity, respectively, moisture content at its simultaneously high temperatures. The cooling of the air at the inlet of a low-speed engine with an ejector chiller by transforming the waste heat of exhaust gases into cold was studied. The ejector chiller is used as the most simple and reliable in operation. However, the efficiency of the transformation of heat into cold by ejector chillers is low - low thermal coefficients.A design solution of the system for cooling air at the inlet of the ship's main engine using the heat of the exhaust gases by an ejector chiller is proposed and analyzed. The effect of using the heat of the exhaust gases to cool the air at the engine inlet is analyzed taking into account the variable climatic conditions during the voyage of the vessel. It is shown that because of the insufficiently high efficiency of transforming the waste heat of the exhaust gases by an ejector chiller (low thermal coefficients), the obtained cooling capacity is not sufficient for cooling the air at the inlet of the turbocompressor during operation of a marine engine in tropical climatic conditions. Therefore, the possibility of use in the ejector chiller of additional heat of charge air, which is removed by cooling water, is also considered. It is shown that the use of the heat of exhaust gases and charge air for cooling the air at the engine inlet in an ejector chiller makes it possible to double decrease the air temperature at the inlet of the main engine by 20-30 °C when the vessel operates in tropical climatic conditions on a voyage lines Shanghai-Singapore-Shanghai. This, in turn, provides an almost twice fuel consumption reduction in compared with its reduction in the case when the ejector chiller uses only the heat of the exhaust gases.

scholarly journals Analytical Design Solution for Optimal Matching of Hybrid Continuous Mode Power Amplifiers Suitable for a High-Efficiency Envelope Tracking Operation

Electronics ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 621
Author(s):  
Tao Cao ◽  
Youjiang Liu ◽  
Wenhua Chen ◽  
Chun Yang ◽  
Jie Zhou
Keyword(s):  
Output Power ◽  
Average Output Power ◽  
High Efficiency ◽  
Average Power ◽  
Experimental System ◽  
Design Solution ◽  
Error Vector Magnitude ◽  
Envelope Tracking ◽  
Average Output ◽  
Power Added Efficiency

An analytical method to design a power amplifier (PA) with an optimized power added efficiency (PAE) trajectory for envelope tracking (ET) architecture is proposed. To obtain feasible matching solutions for high-efficiency performance of the PA in the dynamic supply operation, hybrid continuous modes (HCM) architecture is introduced. The design space for load impedances of the HCM PAs with nonlinear capacitance is deduced mathematically using the device’s embedding transfer network, without the necessity of using load-pull. The proposed design strategy is verified with the implementation of a GaN PA operating over the frequency range of 1.9 GHz to 2.2 GHz with PAE between 67.8% and 72.4% in the 6.7 dB back-off power region of the ET mode. The ET experimental system was set up to evaluate the application of the PA circuit. Measurement results show that the ET PA at 2.1 GHz reaches the efficiency of 61%, 54%, 44% and an error vector magnitude (EVM) of 0.32%, 0.60%, 0.67% at an average output power of 34.4 dBm, 34.2 dBm, 34.1 dBm for 6.7 dB peak-to-average power ratios (PAPR) signals with 5 MHz, 10 MHz, and 20 MHz bandwidths, respectively. Additionally, tested by a 20 MHz bandwidth 16 quadrature amplitude modulation (QAM) signal, 41.8% to 49.2% efficiency of ET PA is achieved at an average output power of 33.5 dBm to 35.1 dBm from 1.9 GHz to 2.2 GHz.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

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