scholarly journals A Didactic Procedure to Solve the Equation of Steady-Static Response in Suspended Cables

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1468
Author(s):  
José Agüero-Rubio ◽  
Javier López-Martínez ◽  
Marta Gómez-Galán ◽  
Ángel-Jesús Callejón-Ferre
Keyword(s):  
Low Voltage ◽  
Tertiary Education ◽  
Vertical Component ◽  
Simple Calculation ◽  
Large Temperature ◽  
Static Response ◽  
Response Equation ◽  
Suspended Cables ◽  
Design Skills ◽  
Line Design

Students in the electrical branch of the short-cycle tertiary education program acquire developmental and design skills for low voltage transmission power lines. Aerial power line design requires mathematical tools not covered well enough in the curricula. Designing suspension cables requires the use of a Taylor series and integral calculation to obtain the parabola’s arc length. Moreover, it requires iterative procedures, such as the Newton–Raphson method, to solve the third-order equation of the steady-static response. The aim of this work is to solve the steady-static response equation for suspended cables using simple calculation tools. For this purpose, the influence of the horizontal component of the cable tension on its curvature was decoupled from the cable’s self-weight, which was responsible for the tension’s vertical component. To this end, we analyzed the laying and operation of the suspended cables by defining three phases (i.e., stressing, lifting, and operation). The phenomena that occurred in each phase were analyzed, as was their manifestation in the cable model. Herein, we developed and validated the solution of the steady-static response equation in suspended cables using simple equations supported with intuitive graphics. The best results of the proposed calculation procedure were obtained in conditions of large temperature variations.

scholarly journals On the simple calculation of walking efficiency without kinematic information for its convenient use

2019 ◽  
Vol 38 (1) ◽  
Author(s):  
Daijiro Abe ◽  
Yoshiyuki Fukuoka ◽  
Masahiro Horiuchi
Keyword(s):  
Regression Line ◽  
Vertical Component ◽  
Young Male ◽  
Simple Calculation ◽  
Potential Candidate ◽  
Gravitational Acceleration ◽  
Inverse Slope ◽  
Mechanical Power Output ◽  
Kinematic Information ◽  
Walking Efficiency

Abstract Background Since walking is a daily activity not to require the maximal effort in healthy populations, a very few universal bio-parameters and/or methods have been defined to evaluate individual walking characteristics in those populations. A concept of “economy” is a potential candidate; however, walking economy highly depends on speed, so direct comparisons of economy values are difficult between studies. We investigated whether the vertical component of net walking “efficiency” (Effvert; %) is constant across speed. In that case, direct comparisons of Effvert will be possible between studies or individuals at any voluntary speed. Methods Thirty young male participants walked at eight speeds on the level or ± 5% gradients, providing vertical speeds (vvert). Differences in energy expenditure between level and uphill or downhill gradients (ΔEE) were calculated. The metabolic rate for vertical component (MRvert) was calculated by multiplying ΔEE with body mass (BM). The mechanical power output for vertical component (Pmech) was calculated by multiplying BM, gravitational acceleration, and vvert. Effvert was obtained from the ratio of Pmech to MRvert at each vvert. Delta efficiency (Delta-E; %) was also calculated from the inverse slope of the regression line representing the relationship of Pmech to MRvert. Results Upward Effvert was nearly constant at around 35% and downward Effvert ranged widely (49–80%). No significant differences were observed between upward Delta-E (35.5 ± 8.8%) and Effvert at any speeds, but not between downward Delta-E (44.9 ± 12.8%) and Effvert. Conclusions Upward ΔEE could be proportional to vvert. Upward, but not downward, Effvert should be useful not only for healthy populations but also for clinical patients to evaluate individual gait characteristics, because it requires only two metabolic measurements on the level and uphill gradients without kinematic information at any voluntary speed. Trial registration UMIN000017690 (R000020501; registered May 26th, 2015, before the first trial) and UMIN000031456 (R000035911; registered Feb. 23rd, 2018, before the first trial).

Inclined Surge Line Design Considerations for Analysis and Monitoring

2019 ◽  
Author(s):  
Jamie Oakman ◽  
Mark Gray ◽  
Benjamin Leber ◽  
Matthew Salac
Keyword(s):  
Monitoring Program ◽  
Large Temperature ◽  
Monitoring Model ◽  
Main Challenge ◽  
Local Stresses ◽  
Fatigue Monitoring ◽  
The Matrix ◽  
Surge Line ◽  
High Degree ◽  
Line Design

Abstract Thermal stratification can occur in pressurizer surge lines when flow rates are low and large temperature differences between the pressurizer fluid and reactor coolant loop fluid exist. NRC Bulletin 88-11 requires that utilities address this issue with respect to the licensing basis. Additionally, significant fatigue usage can develop due to insurges and outsurges from the pressurizer that occur when the temperature difference (ΔT) is large. An important aspect of the surge line fatigue analysis is determination of global pipe moment loads due to insurges, outsurges, and related stratification effects. The Westinghouse AP1000® plant surge line is designed to limit the global effects of stratification using a surge line geometry that is inclined more than that of the previous generation plants. However, this design provides unique challenges to the analytical solution in comparison to the mostly horizontal geometries in previous PWR designs. The main challenge is due to the location of the stratified fluid hot/cold interface. The horizontal geometry has historically allowed conservative (based on analytical testing) treatment of the stratified interface profile. The inclined geometry requires consideration of positional changes, as the stratified interface moves through the line due to flow changes. Because of this, iterative calculations were required to predict global piping moment loads through the transient histories based on the movement of the stratified interface. Software was developed to solve a series of correlative equations representing moment loads due to pipe temperatures and stratification ΔT within discretized portions of the surge line throughout each transient. The correlative equations, which are based on the matrix solution of piping analysis load cases, predict the global pipe moment loads to a high degree of precision. The surge line is also a significant location in the online fatigue monitoring program implemented at the sites. The complexity of the design analysis that is reflected in the monitoring model requires a more detailed accounting for the location of the stratification interface, the effect on prediction of moment loadings for controlling locations, and the effect on local stresses at the monitoring locations. This paper describes the approach used to address all of these factors in the design evaluation and subsequent fatigue monitoring application.

Processing of human melanoma cells for correlative TEM, LVSEM, and LM

1991 ◽  
Vol 49 ◽  
pp. 106-107
Author(s):  
Marek Malecki ◽  
J. Victor Small ◽  
James Pawley
Keyword(s):  
Electron Microscopy ◽  
Low Voltage ◽  
Fluorescent Microscopy ◽  
Blood Stream ◽  
Surface Topology ◽  
Integrin Receptors ◽  
Transmission Electron ◽  
Develop Technology ◽  
Voltage Scanning ◽  
Mechanisms Of Adhesion

The relative roles of adhesion and locomotion in malignancy have yet to be clearly established. In a tumor, subpopulations of cells may be recognized according to their capacity to invade neighbouring tissue,or to enter the blood stream and metastasize. The mechanisms of adhesion and locomotion are themselves tightly linked to the cytoskeletal apparatus and cell surface topology, including expression of integrin receptors. In our studies on melanomas with Fluorescent Microscopy (FM) and Cell Sorter(FACS), we noticed that cells in cultures derived from metastases had more numerous actin bundles, then cells from primary foci. Following this track, we attempted to develop technology allowing to compare ultrastructure of these cells using correlative Transmission Electron Microscopy(TEM) and Low Voltage Scanning Electron Microscopy(LVSEM).

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Development of a conical anode Fe-gun for low voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 978-979
Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
Irradiation Damage ◽  
Cold Cathode ◽  
Virtual Source ◽  
Source Position ◽  
Electrostatic Lens ◽  
Electrostatic Lenses ◽  
Wide Range

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.

SEM analysis of DC magnetron sputtered beryllium films

1988 ◽  
Vol 46 ◽  
pp. 960-961
Author(s):  
E. F. Lindsey ◽  
C. W. Price ◽  
E. L. Pierce ◽  
E. J. Hsieh
Keyword(s):  
Fine Structure ◽  
Electron Emission ◽  
Secondary Electron ◽  
Low Voltage ◽  
Ion Beam ◽  
Secondary Electron Emission ◽  
Sem Analysis ◽  
Fused Silica ◽  
Grain Structure ◽  
Silica Substrate

Columnar structures produced by DC magnetron sputtering can be altered by using RF biased sputtering or by exposing the film to nitrogen pulses during sputtering, and these techniques are being evaluated to refine the grain structure in sputtered beryllium films deposited on fused silica substrates. Beryllium is brittle, and fractures in sputtered beryllium films tend to be intergranular; therefore, a convenient technique to analyze grain structure in these films is to fracture the coated specimens and examine them in an SEM. However, fine structure in sputtered deposits is difficult to image in an SEM, and both the low density and the low secondary electron emission coefficient of beryllium seriously compound this problem. Secondary electron emission can be improved by coating beryllium with Au or Au-Pd, and coating also was required to overcome severe charging of the fused silica substrate even at low voltage. The coating structure can obliterate much of the fine structure in beryllium films, but reasonable results were obtained by using the high-resolution capability of an Hitachi S-800 SEM and either ion-beam coating with Au-Pd or carbon coating by thermal evaporation.

Toward High-Resolution Low-Voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 218-219
Author(s):  
Zhifeng Shao
Keyword(s):  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Operating Voltage ◽  
Probe Radius ◽  
Non Local ◽  
Electron Microscopes ◽  
Image Position ◽  
Scanning Electron Microscopes

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as

High-Resolution, Low-Voltage SEM of Cell Wall Regeneration of Yeast Shizosaccharomyces Pombe Protoplasts

1988 ◽  
Vol 46 ◽  
pp. 208-211
Author(s):  
M. Osumi ◽  
N. Yamada ◽  
T. Nagatani
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Low Voltage ◽  
Cell Wall Regeneration ◽  
The Past ◽  
The Poor ◽  
Probe Size ◽  
Beam Damage ◽  
Biological Field ◽  
Scanning Electron

Even though many early workers had suggested the use of lower voltages to increase topographic contrast and to reduce specimen charging and beam damage, we did not usually operate in the conventional scanning electron microscope at low voltage because of the poor resolution, especially of bioligical specimens. However, the development of the “in-lens” field emission scanning electron microscope (FESEM) has led to marked inprovement in resolution, especially in the range of 1-5 kV, within the past year. The probe size has been cumulated to be 0.7nm in diameter at 30kV and about 3nm at 1kV. We have been trying to develop techniques to use this in-lens FESEM at low voltage (LVSEM) for direct observation of totally uncoated biological specimens and have developed the LVSEM method for the biological field.

Current State of Biological High-Resolution Scanning Electron Microscopy

1988 ◽  
Vol 46 ◽  
pp. 180-181 ◽  
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Performance ◽  
Low Voltage ◽  
Backscattered Electrons ◽  
Lens Position ◽  
Low Voltage Operation ◽  
Signal Collection ◽  
Probe Size ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

A new generation of high performance field emission scanning electron microscopes (FSEM) is now commercially available (JEOL 890, Hitachi S 900, ISI OS 130-F) characterized by an "in lens" position of the specimen where probe diameters are reduced and signal collection improved. Additionally, low voltage operation is extended to 1 kV. Compared to the first generation of FSEM (JE0L JSM 30, Hitachi S 800), which utilized a specimen position below the final lens, specimen size had to be reduced but useful magnification could be impressively increased in both low (1-4 kV) and high (5-40 kV) voltage operation, i.e. from 50,000 to 200,000 and 250,000 to 1,000,000 x respectively.At high accelerating voltage and magnification, contrasts on biological specimens are well characterized1 and are produced by the entering probe electrons in the outmost surface layer within -vl nm depth. Backscattered electrons produce only a background signal. Under these conditions (FIG. 1) image quality is similar to conventional TEM (FIG. 2) and only limited at magnifications >1,000,000 x by probe size (0.5 nm) or non-localization effects (%0.5 nm).

SEM at Low Beam Voltage

1984 ◽  
Vol 42 ◽  
pp. 440-443
Author(s):  
James Pawley
Keyword(s):  
Low Voltage ◽  
Probe Diameter ◽  
Small Probe ◽  
Beam Voltage ◽  
Practical Constraints

Operation of the SEM with V0 = l-3kV (LVSEM) was early recognized to reduce charging artefacts and increase topographic contrast. This early promise was not pursued because several theoretical and practical considerations made it difficult to produce a small probe diameter (d0) at low voltage. Recently, the necessity of using low V0 to image uncoated semiconductors without damaging them has prompted a re-evaluation of LVSEM. This re-evaluation has taken the form of efforts to eliminate the practical constraints and to alleviate the theoretical ones. In the process, some heretofore neglected theoretical advantages of LVSEM have emerged. These problems and possibilities will now be discussed in more detail.

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