Analysis of the conditions for the exhaustion of the stability margin in the rail track of freight cars with three-piece bogies

The research on improvement of methodical approaches to definition of the probable reasons of infringement of conditions of stability of freight cars from derailment is carried out. Using a basic computer model of the dy-namics of a freight car, the influence of the characteristics of the technical condition of their running gear and track on the indicators of empty cars stability from derailment was studied through the computational experi-ment. The article presents the main statements of the research methodology, which provides the analysis of probable causes of derailment of freight cars by conducting a series of numerical experiments with logging the progress of calculations and saving the results. Factor analysis was used to interpret the calculated data with an assessment of each of the factors influence or their combination on the probability of derailment. The developed procedure of the simulation experiment provides a step-by-step study of the freight cars derail-ment conditions, including factors structuring and ranking, development of experimental plan, calculating coef-ficients of wheel pairs resistance to derailment from rails, provided that the wheel flange rolls onto the rail head, and determining the degree of influence of relevant factors on the dynamic stability of cars from derailment. A comparative analysis of the stability of cars in rail tracks was performed using the introduced concept of the combined coefficient of stability of wheel pairs against derailment. Determining the probable causes of car derailment is based on scanning the parameter field. The results of the parametric study revealed the degree of influence on the freight cars stability of running gear technical condition characteristics. In particular, it is determined that the most dangerous in terms of stability loss of empty cars in the track is the exceeding of the wedges of the vibration dampers.

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Postmodern More

Moreana ◽

10.3366/more.2003.40.1-2.14 ◽

2003 ◽

Vol 40 (Number 153- (1-2) ◽

pp. 219-239

Author(s):

Anne Lake Prescott

Keyword(s):

Human Language ◽

Thomas More ◽

The Stability ◽

Definition Of ◽

Recent Critic

Thomas More is often called a “humanist,” and rightly so if the word has its usual meaning in scholarship on the Renaissance. “Humanist” has by now acquired so many different and contradictory meanings, however, that it needs to be applied carefully to the likes of More. Many postmodernists tend to use the word, pejoratively, to mean someone who believes in an autonomous self, the stability of words, reason, and the possibility of determinable meanings. Without quite arguing that More was a postmodernist avant la lettre, this essay suggests that he was not a “humanist” who stalks the pages of much recent postmodernist theory and that in fact even while remaining a devout Catholic and sensible lawyer he was quite as aware as any recent critic of the slipperiness of human selves and human language. It is time that literary critics tightened up their definition of “humanist,” especially when writing about the Renaissance.

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Symmetrizable Difference Dchemes

Computational Methods in Applied Mathematics ◽

10.2478/cmam-2005-0001 ◽

2005 ◽

Vol 5 (1) ◽

pp. 3-50 ◽

Cited By ~ 2

Author(s):

Alexei A. Gulin

Keyword(s):

Initial Data ◽

Difference Scheme ◽

Difference Schemes ◽

Time Dependent ◽

Stability Boundaries ◽

Typical Representative ◽

Variable Weight ◽

The Stability ◽

Conditions Of Stability ◽

The Right

AbstractA review of the stability theory of symmetrizable time-dependent difference schemes is represented. The notion of the operator-difference scheme is introduced and general ideas about stability in the sense of the initial data and in the sense of the right hand side are formulated. Further, the so-called symmetrizable difference schemes are considered in detail for which we manage to formulate the unimprovable necessary and su±cient conditions of stability in the sense of the initial data. The schemes with variable weight multipliers are a typical representative of symmetrizable difference schemes. For such schemes a numerical algorithm is proposed and realized for constructing stability boundaries.

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Renovation Management Method in Neglected Buildings

Sustainability ◽

10.3390/su13020929 ◽

2021 ◽

Vol 13 (2) ◽

pp. 929

Author(s):

Beata Nowogońska ◽

Magdalena Mielczarek

Keyword(s):

Decision Making ◽

Technical Condition ◽

Irreversible Processes ◽

Management Method ◽

The Stability ◽

Motivating Factor ◽

Decision Making Support

Renovation works to buildings are often not carried out or there are shifts in time, which causes degradation of the building. The article presents an analysis of the consequences of abandoning renovation works. The aim of this article is to present a method of preliminarily planning renovations of a MRUB (Managing Renovation in Un-renovated Buildings). This method of decision-making support is based on the consequences in the case of the omission of renovations. The omission of renovations may lead to a threat to the stability of the building’s structure, threaten the lives of its users, and further damage the building by damaging further elements, or even cause a building disaster. Often, as a result of the abandonment of renovation, usually caused by the lack of the owner, improper manager, or irresponsible owners, these objects are degraded. The consequences of the failure of renovating buildings lead to irreversible processes of destruction. As a result of the research, it was found that it was not only a bad technical condition that was a prerequisite for carrying out the renovation. The consequences of the absence of renovation works, in addition to the technical condition, should be a motivating factor. The problem of the abandonment of renovations is presented using the example of the palace in Drwalewice.

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Influence of study model, baseline catalytic concentrations and analytical system on the stability of serum alanine aminotransferase

Advances in Laboratory Medicine / Avances en Medicina de Laboratorio ◽

10.1515/almed-2020-0021 ◽

2020 ◽

Vol 1 (2) ◽

Author(s):

Josep Miquel Bauça ◽

Andrea Caballero ◽

Carolina Gómez ◽

Débora Martínez-Espartosa ◽

Isabel García del Pino ◽

...

Keyword(s):

Alanine Aminotransferase ◽

Experimental Models ◽

Individual Variability ◽

Serum Samples ◽

Multicentric Study ◽

Different Temperatures ◽

The Stability ◽

Analytical System ◽

Definition Of ◽

Analytical Platforms

AbstractObjectivesThe stability of the analytes most commonly used in routine clinical practice has been the subject of intensive research, with varying and even conflicting results. Such is the case of alanine aminotransferase (ALT). The purpose of this study was to determine the stability of serum ALT according to different variables.MethodsA multicentric study was conducted in eight laboratories using serum samples with known initial catalytic concentrations of ALT within four different ranges, namely: <50 U/L (<0.83 μkat/L), 50–200 U/L (0.83–3.33 μkat/L), 200–400 U/L (3.33–6.67 μkat/L) and >400 U/L (>6.67 μkat/L). Samples were stored for seven days at two different temperatures using four experimental models and four laboratory analytical platforms. The respective stability equations were calculated by linear regression. A multivariate model was used to assess the influence of different variables.ResultsCatalytic concentrations of ALT decreased gradually over time. Temperature (−4%/day at room temperature vs. −1%/day under refrigeration) and the analytical platform had a significant impact, with Architect (Abbott) showing the greatest instability. Initial catalytic concentrations of ALT only had a slight impact on stability, whereas the experimental model had no impact at all.ConclusionsThe constant decrease in serum ALT is reduced when refrigerated. Scarcely studied variables were found to have a significant impact on ALT stability. This observation, added to a considerable inter-individual variability, makes larger studies necessary for the definition of stability equations.

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Stability-Guaranteed and High Terrain Adaptability Static Gait for Quadruped Robots

Sensors ◽

10.3390/s20174911 ◽

2020 ◽

Vol 20 (17) ◽

pp. 4911

Author(s):

Qian Hao ◽

Zhaoba Wang ◽

Junzheng Wang ◽

Guangrong Chen

Keyword(s):

Impedance Control ◽

Stability Margin ◽

Planning Method ◽

Legged Robots ◽

Gait Planning ◽

Quadruped Locomotion ◽

Quadruped Robots ◽

Adjustment Strategy ◽

Compliant Behavior ◽

The Stability

Stability is a prerequisite for legged robots to execute tasks and traverse rough terrains. To guarantee the stability of quadruped locomotion and improve the terrain adaptability of quadruped robots, a stability-guaranteed and high terrain adaptability static gait for quadruped robots is addressed. Firstly, three chosen stability-guaranteed static gaits: intermittent gait 1&2 and coordinated gait are investigated. In addition, then the static gait: intermittent gait 1, which is with the biggest stability margin, is chosen to do a further research about quadruped robots walking on rough terrains. Secondly, a position/force based impedance control is employed to achieve a compliant behavior of quadruped robots on rough terrains. Thirdly, an exploratory gait planning method on uneven terrains with touch sensing and an attitude-position adjustment strategy with terrain estimation are proposed to improve the terrain adaptability of quadruped robots. Finally, the proposed methods are validated by simulations.

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Study on the characteristics of secondary arc current of UHV high compensation degree TCSC line under the fine-tuning mode

International Journal of Emerging Electric Power Systems ◽

10.1515/ijeeps-2020-0202 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Baina He ◽

Yadi Xie ◽

Jingru Zhang ◽

Nirmal-Kumar C. Nair ◽

Xingmin He ◽

...

Keyword(s):

Transmission Line ◽

Transmission Lines ◽

Stability Margin ◽

Transmission Capacity ◽

Fine Tuning ◽

Series Compensation ◽

Arc Current ◽

Compensation Device ◽

The Stability ◽

Recovery Voltage

Abstract In the transmission line, the series compensation device is often used to improve the transmission capacity. However, when the fixed series capacitor (FSC) is used in high compensation series compensation device, the stability margin cannot meet the requirements. Therefore, thyristor controlled series compensator (TCSC) is often installed in transmission lines to improve the transmission capacity of the line and the stability of the system. For cost considerations, the hybrid compensation mode of FSC and TCSC is often adopted. However, when a single-phase grounding fault occurs in a transmission line with increased series compensation degree, the unreasonable distribution of FSC and TCSC will lead to the excessive amplitude of secondary arc current, which is not conducive to rapid arc extinguishing. To solve this problem, this paper is based on 1000 kV Changzhi-Nanyang-Jingmen UHV series compensation transmission system, using PSCAD simulation program to established UHV series compensation simulation model, The variation law of secondary arc current and recovery voltage during operation in fine tuning mode after adding TCSC to UHV transmission line is analyzed, and the effect of increasing series compensation degree on secondary arc current and recovery voltage characteristics is studied. And analyze the secondary arc current and recovery voltage when using different FSC and TCSC series compensation degree schemes, and get the most reasonable series compensation configuration scheme. The results show that TCSC compensation is more beneficial to arc extinguishing under the same series compensation. Compared with several series compensation schemes, it is found that with the increase of the proportion of TCSC, the amplitude of secondary arc current and recovery voltage vary greatly. Considering various factors, the scheme that is more conducive to accelerating arc extinguishing is chosen.

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Reliable Learning with PDE-Based CNNs and DenseNets for Detecting COVID-19, Pneumonia, and Tuberculosis from Chest X-Ray Images

Mathematics ◽

10.3390/math9040434 ◽

2021 ◽

Vol 9 (4) ◽

pp. 434

Author(s):

Anca Nicoleta Marginean ◽

Delia Doris Muntean ◽

George Adrian Muntean ◽

Adelina Priscu ◽

Adrian Groza ◽

...

Keyword(s):

Transfer Learning ◽

Negative Impact ◽

X Ray ◽

Domain Specific ◽

Direct Training ◽

Public Data ◽

Normal Chest ◽

Chest X Ray ◽

The Stability ◽

Definition Of

It has recently been shown that the interpretation by partial differential equations (PDEs) of a class of convolutional neural networks (CNNs) supports definition of architectures such as parabolic and hyperbolic networks. These networks have provable properties regarding the stability against the perturbations of the input features. Aiming for robustness, we tackle the problem of detecting changes in chest X-ray images that may be suggestive of COVID-19 with parabolic and hyperbolic CNNs and with domain-specific transfer learning. To this end, we compile public data on patients diagnosed with COVID-19, pneumonia, and tuberculosis, along with normal chest X-ray images. The negative impact of the small number of COVID-19 images is reduced by applying transfer learning in several ways. For the parabolic and hyperbolic networks, we pretrain the networks on normal and pneumonia images and further use the obtained weights as the initializers for the networks to discriminate between COVID-19, pneumonia, tuberculosis, and normal aspects. For DenseNets, we apply transfer learning twice. First, the ImageNet pretrained weights are used to train on the CheXpert dataset, which includes 14 common radiological observations (e.g., lung opacity, cardiomegaly, fracture, support devices). Then, the weights are used to initialize the network which detects COVID-19 and the three other classes. The resulting networks are compared in terms of how well they adapt to the small number of COVID-19 images. According to our quantitative and qualitative analysis, the resulting networks are more reliable compared to those obtained by direct training on the targeted dataset.

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Measurement of Angular Acceleration of a Rigid Body Using Linear Accelerometers

Journal of Applied Mechanics ◽

10.1115/1.3423640 ◽

1975 ◽

Vol 42 (3) ◽

pp. 552-556 ◽

Cited By ~ 377

Author(s):

A. J. Padgaonkar ◽

K. W. Krieger ◽

A. I. King

Keyword(s):

Experimental Data ◽

Rigid Body ◽

Simple Procedure ◽

Three Dimensional ◽

Angular Acceleration ◽

Theory And Practice ◽

Body Segments ◽

Impact Biomechanics ◽

The Stability ◽

Definition Of

The computation of angular acceleration of a rigid body from measured linear accelerations is a simple procedure, based on well-known kinematic principles. It can be shown that, in theory, a minimum of six linear accelerometers are required for a complete definition of the kinematics of a rigid body. However, recent attempts in impact biomechanics to determine general three-dimensional motion of body segments were unsuccessful when only six accelerometers were used. This paper demonstrates the cause for this inconsistency between theory and practice and specifies the conditions under which the method fails. In addition, an alternate method based on a special nine-accelerometer configuration is proposed. The stability and superiority of this approach are shown by the use of hypothetical as well as experimental data.

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