Dornhonen ohne Kühlschmierstoff/Single-pass honing without cooling lubricant – Feasibility of a dry honing process and determination of the effects during machining

2021 ◽  
Vol 111 (07-08) ◽  
pp. 520-525
Author(s):  
Eckart Uhlmann ◽  
André Rozek ◽  
Sascha Zimmermann
Keyword(s):  
State Of The Art ◽  
Low Frequency ◽  
Single Pass ◽  
Current State ◽  
Low Frequency Oscillations ◽  
Process Forces ◽  
Cooling Lubricant ◽  
Chip Removal

Bei der Intensivzerspanung mit einem bohrungsfüllenden Werkzeug ist nach heutigem Wissensstand der Einsatz von Kühlschmierstoffen obligatorisch. Jüngste Untersuchungen haben gezeigt, dass eine Überlagerung niederfrequenter Schwingungen beim Dornhonen die Spanabfuhr, die Prozesskräfte- und momente sowie die Arbeitsergebnisse positiv beeinflusst. Darauf aufbauend wurde in dieser Arbeit das schwingungsüberlagerte Dornhonen ohne Kühlschmierstoff untersucht.   According to the current state-of-the-art, the application of cooling lubricants is mandatory while using a bore-filling tool for intensive machining. Recent investigations have shown that a superposition of low-frequency oscillations in single-pass honing improves the local chip removal and work results while reducing process forces and torques. Following this, the oscillation-superimposed single-pass honing without cooling lubricant has been conducted in this work.

scholarly journals Earth Orientation - The Current and Future Situation

1995 ◽  
Vol 166 ◽  
pp. 287-291
Author(s):  
Dennis D. McCarthy
Keyword(s):  
State Of The Art ◽  
International Earth Rotation Service ◽  
Earth Orientation Parameters ◽  
Earth Orientation ◽  
Current State ◽  
The Earth ◽  
Future Situation ◽  
Orientation Parameters

Sub-milliarcsecond astrometry often requires an accurate characterization of the orientation of the Earth in a quasi-inertial reference frame. The International Earth Rotation Service (IERS) standards provide the current state of the art in the transformation between celestial and terrestrial reference systems. Improvements in the determination of Earth orientation parameters which describe this transformation continue to be made. Current and future capabilities are given.

scholarly journals Radio observatories and instrumentation used in space weather science and operations

2020 ◽  
Vol 10 ◽  
pp. 7 ◽  
Author(s):  
Eoin P. Carley ◽  
Carla Baldovin ◽  
Pieter Benthem ◽  
Mario M. Bisi ◽  
Richard A. Fallows ◽  
...  
Keyword(s):  
Space Weather ◽  
Phased Array ◽  
Service Providers ◽  
State Of The Art ◽  
Low Frequency ◽  
The Sun ◽  
Frequency Range ◽  
Current State ◽  
Near Future ◽  
Entire Array

The low frequency array (LOFAR) is a phased array interferometer currently consisting of 13 international stations across Europe and 38 stations surrounding a central hub in the Netherlands. The instrument operates in the frequency range of ~10–240 MHz and is used for a variety of astrophysical science cases. While it is not heliophysics or space weather dedicated, a new project entitled “LOFAR for Space Weather” (LOFAR4SW) aims at designing a system upgrade to allow the entire array to observe the Sun, heliosphere, Earth’s ionosphere, and Jupiter throughout its observing window. This will allow the instrument to operate as a space weather observing platform, facilitating both space weather science and operations. Part of this design study aims to survey the existing space weather infrastructure operating at radio frequencies and show how LOFAR4SW can advance the current state-of-the-art in this field. In this paper, we survey radio instrumentation and facilities that currently operate in space weather science and/or operations, including instruments involved in solar, heliospheric, and ionospheric studies. We furthermore include an overview of the major space weather service providers in operation today and the current state-of-the-art in the radio data they use and provide routinely. The aim is to compare LOFAR4SW to the existing radio research infrastructure in space weather and show how it may advance both space weather science and operations in the radio domain in the near future.

scholarly journals Research of micro and nano profile surface morphology of vibrational mechanical and chemical zinc coating

2018 ◽  
Vol 226 ◽  
pp. 01018 ◽  
Author(s):  
Vladimir V. Ivanov ◽  
Nikolay P. Pogorelov ◽  
Mikhail F. Selemenev ◽  
Artem A. Sakunov
Keyword(s):  
Surface Morphology ◽  
Processing Time ◽  
Coating Layer ◽  
Zinc Coating ◽  
Low Frequency ◽  
Reliable Data ◽  
Technological Systems ◽  
Low Frequency Oscillations ◽  
The Given

There are some results of zinc coating research acquired on the metals’ surface as a result of mechanical and chemical synthesis, realized in conditions of vibro wave technological systems. The peculiarities of the surface morphology at the micro / nano level of the zinc coating are shown which are formed under the influence of low-frequency oscillations. The growth interconnection of the micro / nano profile of the applied zinc coating is shown. The determination of changes occurring on the coating layer surface at the micro / nano level. The absence of reliable data of the surface layer of the coating at the nano level has significantly limited its modification background. All of the mentioned above brings up to the following task, the given article is devoted to its solution: establishment of particlesdimension, the way of their distribution on the metal surface, besidestheir maximal and minimal roughness data cause by the alteration of the processing time.

scholarly journals Investigation of the process of peeling walnuts between two parallel plates

2019 ◽  
pp. 110-117
Author(s):  
Yurii Polievoda
Keyword(s):  
Driving Force ◽  
Low Frequency ◽  
Parallel Plates ◽  
Technological Parameters ◽  
Low Frequency Oscillations ◽  
Crushing Force ◽  
Perpendicular Crack ◽  
Vertical Positioning ◽  
Brittle Destruction

The article provides a detailed overview of the process of splitting the kernel of a walnut. Examples of many ways to split the shell are given, all of their disadvantages and advantages are listed. The mechanical method of peeling nuts using low-frequency oscillations has been theoretically investigated and substantiated. The kinematics of the process of crushing nuts between two parallel plates has been extensively analyzed. Graphical correlations were obtained between the size of the nut shell and the dynamics of the driving force of the nut moisture. It is revealed that the process of destruction of the shell of a walnut consists of four stages, corresponding to the laws of brittle destruction. Presents: - dependence of the maximum force of crushing of a shell of a nut at 5% humidity; - the dependence of the maximum crushing force of nuts at different shell thickness for the case of horizontal positioning of the nut between two plates with perpendicular force on the surface of the joint halves of the nut; - the dependence of the maximum crushing force according to the humidity of the nuts at different shell thicknesses for the case of vertical positioning of the nut between two parallel plates with a vertical driving force; - the dependence of the maximum crushing force with the moisture of the nuts at different shell thicknesses for the case of horizontal positioning of the nut between two parallel plates with a force action along the slit. The energy of splitting (crushing) of nuts at their location in different positions between two parallel plates is also determined. Where it has been proved that the energy consumed in the process of crushing increases with the thickness of the shell of a walnut. At the same time, it is proved that energy consumption depends on the location of the nut in the process of crushing. Graph analyzes were performed to show that maximum crushing energy is recorded in the case of a horizontal arrangement of a nut with a perpendicular crack action. In this study, a large amount of information was obtained regarding the splitting of the walnut, depending on the structural and mechanical characteristics of the products, which in the process of processing are important for the determination of certain rational technological parameters.

Some Issues Concerning Fluid-Elastic Instability of a Group of Circular Cylinders in Cross-Flow

1989 ◽  
Vol 111 (4) ◽  
pp. 507-518 ◽  
Author(s):  
S. S. Chen
Keyword(s):  
Flow Velocity ◽  
State Of The Art ◽  
Cross Flow ◽  
Circular Cylinders ◽  
Critical Flow ◽  
Elastic Instability ◽  
Stability Criteria ◽  
Critical Flow Velocity ◽  
Current State

Since the early 1970s, extensive studies of fluid-elastic instability of circular cylinders in cross-flow have been reported. A significant understanding of the phenomena involved now exists. However, some confusion, misunderstanding, and misinterpretation still remain. The objective of this paper is to discuss, based on the current state of the art, a series of the most asked questions. Emphasis is placed on the determination of the critical flow velocity, nondimensional parameters, stability criteria, and instability mechanisms.

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