Design and execution of the shield drive for the Nurnberg subway using the improved design mix shield for the first time in rock and loose soil (in German and English)

1989 ◽  
Vol 26 (5) ◽  
pp. 254
Keyword(s):  
Loose Soil ◽  
Improved Design ◽  
First Time

Autonomous performance maximization of research-based hybrid unmanned aerial vehicle

2020 ◽  
Vol 92 (4) ◽  
pp. 645-651
Author(s):  
Sezer Çoban
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Performance Optimization ◽  
Flight Trajectory ◽  
Content Type ◽  
Lateral Dynamics ◽  
Aerial Vehicle ◽  
Improved Design ◽  
Autopilot Systems ◽  
First Time ◽  
Practical Implications

Purpose This paper aims to investigate the autonomous performance optimization of a research-based hybrid unmanned aerial vehicle (i.e. HUAV) manufactured at Iskenderun Technical University. Design/methodology/approach To maximize the autonomous performance of this HUAV, longitudinal and lateral dynamics were initially obtained. Then, the optimum magnitudes of the autopilot system parameters were estimated by considering the vehicle’s dynamic model and autopilot parameters. Findings After determining the optimum values of the longitudinal and lateral autopilots, an improved design for the autonomously controlled (AC) HUAV was achieved in terms of real-time flight. Practical implications Simultaneous improvement of the longitudinal and lateral can be used for better HUAV operations. Originality/value In this paper, the autopilot systems (i.e. longitudinal and lateral) of an HUAV are for the first time simultaneously designed in the literature. This helps the simultaneous improvement of the longitudinal and lateral flight trajectory tracking performances.

IMPROVED DESIGN OF A HEAD OF A TOTAL HIP REPLACEMENT

2020 ◽  
Vol 4 (1) ◽  
pp. 139-143
Author(s):  
V.I. PAKHALIUK ◽  
A.M. POLIAKOV
Keyword(s):  
Titanium Alloy ◽  
Total Hip Replacement ◽  
Hip Replacement ◽  
Low Cost ◽  
Friction Couple ◽  
Element Analysis ◽  
Total Hip ◽  
Improved Design ◽  
First Time ◽  
Soldered Joint

For the first time, the design of a modular ceramic head of a total hip replacement (THR) has been developed, which has the properties of a metal in join with the stem neck and the properties of a ceramic on the bearing surface of a friction couple. This is achieved by creating a low-cost, low-toxic, strong connection of alumina or zirconium ceramics and a titanium alloy to obtain a soldered joint that is efficient in human synovial fluid. With the help of finite element analysis, a qualitative and quantitative assessment of the strength and rigidity of the proposed head design has been made. Also shown is an image of a finished soldered head made of alumina ceramic with a sleeve made of titanium alloy VT1-0.

scholarly journals IMPROVED DESIGN TECHNIQUE FOR CONDUCTING PARTS OF ELECTROMAGNETIC CONTACTORS

2021 ◽  
pp. 73-82
Author(s):  
Ivan P. Ivanov ◽  
Dmitriy V. Samuilov ◽  
Gennadiy P. Svintsov ◽  
Alexey A. Fedimirov ◽  
Evgeniy V. Shpakov
Keyword(s):  
Temperature Distribution ◽  
Heating Temperature ◽  
Infinite Length ◽  
Design Technique ◽  
Distribution Constant ◽  
Improved Design ◽  
Almost All ◽  
Improved Technique ◽  
First Time

The existing design techniques for the conductive parts of the main circuit of electromagnetic contactors are based on two assumptions: the infinite length of the conductor and the absence of its heating, which is determined by the contact resistance. This can lead to significant errors in the design of conductors of finite length, primarily in the design of conductive parts with contact bridges, which contain almost all modern electromagnetic contactors. For a more efficient determination of the geometric parameters of the conductive parts, it is proposed to use an improved technique without the above assumptions. The technique uses a model of a contact formed by overlapping the ends of two rectangular conductors and containing a contact piece as a design one. A key feature of the technique is the use in the calculations of the temperature distribution constant along the length of the conductor, introduced for the first time, which determines the nature of the change in its heating temperature. The main stages of calculation and an example of determining the geometric dimensions of the conductive parts by this method for ABB contactors for different rated currents are given.

scholarly journals Measurement of the polarisation in the auroral N2+ 427.8 nm band

2019 ◽  
Vol 9 ◽  
pp. A26 ◽  
Author(s):  
Mathieu Barthelemy ◽  
Hervé Lamy ◽  
Anne Vialatte ◽  
Magnar Gullikstad Johnsen ◽  
Gaël Cessateur ◽  
...  
Keyword(s):  
Emission Lines ◽  
Data Set ◽  
Auroral Emission ◽  
Integration Period ◽  
Data Analysis Procedure ◽  
Improved Design ◽  
Blue Line ◽  
The Individual ◽  
First Time ◽  
Linear Polarisation

In this paper, we provide for the first time polarisation measurements of the N+2 band at 427.8 nm performed with Premier Cru, a dedicated spectropolarimeter to investigate the polarisation of auroral emission lines between 400 and 700 nm. Details about the instrument, the observing conditions and the data analysis procedure are provided. Results obtained during three nights in March 2017 in Skibotn, Norway, indicate that the auroral blue line is polarised with a degree of linear polarisation of a few %. Due to weak Signal-to-Noise Ratios (SNR), these measurements still need to be taken with caution since none of the individual data set has a detection with a 3σ confidence level. However, results integrated over the entire observing period each night do show a 3σ detection but due to the long integration period, the origin of this polarisation cannot be linked to a specific type of aurora (diffuse vs structured arc) or specific ionospheric or geomagnetic conditions. These observations need to be confirmed with an improved design to increase the SNR and decrease the exposure time. When available, these improved measurements of the blue line polarisation will be important to better understand the physics of auroral processes at altitudes below 100 km where the N2+ emission occurs and possibly for space weather applications if the polarisation varies with ionospheric/geomagnetic conditions.

scholarly journals Ways to Increase the Efficiency of Thermopressiometry

2021 ◽  
pp. 84-91
Author(s):  
V. Y Ulyanov
Keyword(s):  
Deformation Modulus ◽  
Probe Design ◽  
Frozen Soils ◽  
Engineering Research ◽  
Soil Sediment ◽  
Thawing Depth ◽  
Sediment Deformation ◽  
Improved Design ◽  
First Time ◽  
Conductive System

Purpose. The purpose of the work is to identify the ways to increase the efficiency of engineering research, based on the significant amount of exploration work required in the creation of modern man-made objects, taking into account the shortcomings of existing instruments and equipment used to measure soil stress, and in relation to the need to improve the design of thermopressiometers, which are aimed to facilitate the study of frozen soils. Methodology. The ways to improve the blade thermopressiometer for the study of frozen soils with different aggregates were selected by the comparative-analytical method and the method of analogy. Thawing depth, absolute soil sediment, deformation modulus etc. were determined by thermal-technical calculations. Findings. The application issues of concern of the existing thermopressiometers (limited research of soils of a certain type, complexity and insufficient accuracy of readings) identified can be overcome by the proposed improved design of a blade thermopressiometer for testing frozen sandy-clay soils. It is based on the improved heating circuit, the applicationd of quality materials and changing the form of the blades and body. The device is intented for use on permafrost and natural frozen soils of the world, including Ukraine. Originality. For the first time we offered a model of an advanced thermopressiometer with an improved body shape made of high-quality corrosion-resistant materials, including non-metallic ones. It has the reduced number of blades to one retractable sector blade-stamp (square or round) and one heating blade-stamp. A special probe design with mechanical/hydraulical sensor drive with a thermocouple (or with two fork probes to improve the measurements) was proposed. It was also recommended to introduce an electric conductive system designed for thawed soils, with a rod for measuring the retractable blade-stamp. The possibility of using a thermopressiometer during the study of seasonally frozen soils is established. Practical value. Improving the device model should facilitate its application in engineering and geological research for various types of construction, including transport, hydraulic engineering, which use the methods of deep freezing of weak and unstable soils.

Annulate lamellae in the Sertoli cells of guinea pig testis after unilateral torsion of the spermatic cord

1984 ◽  
Vol 42 ◽  
pp. 196-197
Author(s):  
J. Chakraborty ◽  
A. P. Sinha Hikim ◽  
J. S. Jhunjhunwala
Keyword(s):  
Sertoli Cells ◽  
Guinea Pigs ◽  
Spermatic Cord ◽  
Present Report ◽  
Cell Types ◽  
Annulate Lamellae ◽  
Spermatogenic Cells ◽  
Electron Microscopic ◽  
Structural Details ◽  
First Time

Although the presence of annulate lamellae was noted in many cell types, including the rat spermatogenic cells, this structure was never reported in the Sertoli cells of any rodent species. The present report is based on a part of our project on the effect of torsion of the spermatic cord to the contralateral testis. This paper describes for the first time, the fine structural details of the annulate lamellae in the Sertoli cells of damaged testis from guinea pigs.One side of the spermatic cord of each of six Hartly strain adult guinea pigs was surgically twisted (540°) under pentobarbital anesthesia (1). Four months after induction of torsion, animals were sacrificed, testes were excised and processed for the light and electron microscopic investigations. In the damaged testis, the majority of seminiferous tubule contained a layer of Sertoli cells with occasional spermatogonia (Fig. 1). Nuclei of these Sertoli cells were highly pleomorphic and contained small chromatinic clumps adjacent to the inner aspect of the nuclear envelope (Fig. 2).

Electron spectroscopic imaging and diffraction

1991 ◽  
Vol 49 ◽  
pp. 706-707
Author(s):  
M. Rühle ◽  
J. Mayer ◽  
J.C.H. Spence ◽  
J. Bihr ◽  
W. Probst ◽  
...  
Keyword(s):  
Materials Science ◽  
Electron Spectroscopic Imaging ◽  
Magnetic Filter ◽  
Magnetic Imaging ◽  
Illumination System ◽  
Probe Size ◽  
Diffraction Patterns ◽  
Fritz Haber ◽  
Koehler Illumination ◽  
First Time

A new Zeiss TEM with an imaging Omega filter is a fully digitized, side-entry, 120 kV TEM/STEM instrument for materials science. The machine possesses an Omega magnetic imaging energy filter (see Fig. 1) placed between the third and fourth projector lens. Lanio designed the filter and a prototype was built at the Fritz-Haber-Institut in Berlin, Germany. The imaging magnetic filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient area detection. The energy dispersion at the exit slit (Fig. 1) results in ∼ 1.5 μm/eV which allows imaging with energy windows of ≤ 10 eV. The smallest probe size of the microscope is 1.6 nm and the Koehler illumination system is used for the first time in a TEM. Serial recording of EELS spectra with a resolution < 1 eV is possible. The digital control allows X,Y,Z coordinates and tilt settings to be stored and later recalled.

A Novel TEM Technique for Characterizing As-Grown CVD Diamond Films

1991 ◽  
Vol 49 ◽  
pp. 956-957 ◽  
Author(s):  
Z.L. Wang ◽  
J. Bentley ◽  
R.E. Clausing ◽  
L. Heatherly ◽  
L.L. Horton
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Dark Field ◽  
Growth Surface ◽  
Specimen Preparation ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
First Time ◽  
Microstructural Studies

Microstructural studies by transmission electron microscopy (TEM) of diamond films grown by chemical vapor deposition (CVD) usually involve tedious specimen preparation. This process has been avoided with a technique that is described in this paper. For the first time, thick as-grown diamond films have been examined directly in a conventional TEM without thinning. With this technique, the important microstructures near the growth surface have been characterized. An as-grown diamond film was fractured on a plane containing the growth direction. It took about 5 min to prepare a sample. For TEM examination, the film was tilted about 30-45° (see Fig. 1). Microstructures of the diamond grains on the top edge of the growth face can be characterized directly by transmitted electron bright-field (BF) and dark-field (DF) images and diffraction patterns.

An improved design for an Scanning Tunnelling Microscope (STM) for use in a Transmission Electron Microscope (TEM)

1991 ◽  
Vol 49 ◽  
pp. 384-385
Author(s):  
W.K. Lo ◽  
J.C.H. Spence
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Mechanical Stability ◽  
Scanning Tunnelling Microscope ◽  
Reflection Mode ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Improved Design

An improved design for a combination Scanning Tunnelling Microscope/TEM specimen holder is presented. It is based on earlier versions which have been used to test the usefulness of such a device. As with the earlier versions, this holder is meant to replace the standard double-tilt specimen holder of an unmodified Philips 400T TEM. It allows the sample to be imaged simultaneously by both the STM and the TEM when the TEM is operated in the reflection mode (see figure 1).The resolution of a STM is determined by its tip radii as well as its stability. This places strict limitations on the mechanical stability of the tip with respect to the sample. In this STM the piezoelectric tube scanner is rigidly mounted inside the endcap of the STM holder. The tip coarse approach to the sample (z-direction) is provided by an Inchworm which is located outside the TEM vacuum.

A microscopic marker experiment study on high temperature oxidation of Ni-Al alloy

1986 ◽  
Vol 44 ◽  
pp. 514-515
Author(s):  
Shou-kong Fan
Keyword(s):  
Transport Mechanism ◽  
High Temperature Oxidation ◽  
Transverse Section ◽  
Al Alloy ◽  
Metal Interface ◽  
Electron Microscopic ◽  
Temperature Oxidation ◽  
Analytical Electron ◽  
Microscopic Studies ◽  
First Time

Transmission and analytical electron microscopic studies of scale microstructures and microscopic marker experiments have been carried out in order to determine the transport mechanism in the oxidation of Ni-Al alloy. According to the classical theory, the oxidation of nickel takes place by transport of Ni cations across the scale forming new oxide at the scale/gas interface. Any markers deposited on the Ni surface are expected to remain at the scale/metal interface after oxidation. This investigation using TEM transverse section techniques and deposited microscopic markers shows a different result,which indicates that a considerable amount of oxygen was transported inward. This is the first time that such fine-scale markers have been coupled with high resolution characterization instruments such as TEM/STEM to provide detailed information about evolution of oxide scale microstructure.

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