scholarly journals Gearbox Mechanical Efficiency Determination by Strain Gauges Direct Application

2021 ◽  
Vol 11 (23) ◽  
pp. 11150
Author(s):  
František Lopot ◽  
Martin Dub ◽  
Jan Flek ◽  
Daniel Hadraba ◽  
Martin Havlíček ◽  
...  
Keyword(s):  
Fem Analysis ◽  
Mechanical Efficiency ◽  
Functional Condition ◽  
Strain Gauges ◽  
Torque Measurement ◽  
Current Configuration ◽  
Unique Method ◽  
The Given ◽  
Efficiency Determination ◽  
Better Than

This article describes a unique method of measuring the efficiency of gearboxes using foil strain gauges, which allows maintaining the current configuration of the gearbox within the overall assembly of the machine and its functional condition. The presented method is applicable to gearboxes located in the original equipment assembly without the need to use a test rig. Using foil strain gauges, the torque at the input and output of the gearbox is detected. Therefore, the accuracy of torque measurement is key. The crucial step is the calibration of the instrumentation to the given application conditions, which, in this case, is ensured by a virtual calibration using a very accurate FEM analysis. The accuracy of the position of strain gauges and virtual calibration of measurements generate inaccuracies affecting the resulting uncertainty of the determined efficiency. The present article shows, on the example of several measurements, that when using 24-bit converters, after processing the obtained data, mechanical stress with a sensitivity better than hundredths of an MPa can be reliably detected even without signal amplification from strain gauges. It follows that the efficiency is determined with an accuracy of better than low units of tenths.

A validated robust and automatic procedure for vibration analysis of bridge structures using MEMS accelerometers

2020 ◽  
Vol 14 (3) ◽  
pp. 327-354
Author(s):  
Mohammad Omidalizarandi ◽  
Ralf Herrmann ◽  
Boris Kargoll ◽  
Steffen Marx ◽  
Jens-André Paffenholz ◽  
...  
Keyword(s):  
Vibration Analysis ◽  
Damping Ratio ◽  
Fem Analysis ◽  
Cost Effective ◽  
Analysis Procedure ◽  
Modal Parameters ◽  
Bridge Structure ◽  
Modal Damping ◽  
Mems Accelerometers ◽  
Better Than

AbstractToday, short- and long-term structural health monitoring (SHM) of bridge infrastructures and their safe, reliable and cost-effective maintenance has received considerable attention. From a surveying or civil engineer’s point of view, vibration-based SHM can be conducted by inspecting the changes in the global dynamic behaviour of a structure, such as natural frequencies (i. e. eigenfrequencies), mode shapes (i. e. eigenforms) and modal damping, which are known as modal parameters. This research work aims to propose a robust and automatic vibration analysis procedure that is so-called robust time domain modal parameter identification (RT-MPI) technique. It is novel in the sense of automatic and reliable identification of initial eigenfrequencies even closely spaced ones as well as robustly and accurately estimating the modal parameters of a bridge structure using low numbers of cost-effective micro-electro-mechanical systems (MEMS) accelerometers. To estimate amplitude, frequency, phase shift and damping ratio coefficients, an observation model consisting of: (1) a damped harmonic oscillation model, (2) an autoregressive model of coloured measurement noise and (3) a stochastic model in the form of the heavy-tailed family of scaled t-distributions is employed and jointly adjusted by means of a generalised expectation maximisation algorithm. Multiple MEMS as part of a geo-sensor network were mounted at different positions of a bridge structure which is precalculated by means of a finite element model (FEM) analysis. At the end, the estimated eigenfrequencies and eigenforms are compared and validated by the estimated parameters obtained from acceleration measurements of high-end accelerometers of type PCB ICP quartz, velocity measurements from a geophone and the FEM analysis. Additionally, the estimated eigenfrequencies and modal damping are compared with a well-known covariance driven stochastic subspace identification approach, which reveals the superiority of our proposed approach. We performed an experiment in two case studies with simulated data and real applications of a footbridge structure and a synthetic bridge. The results show that MEMS accelerometers are suitable for detecting all occurring eigenfrequencies depending on a sampling frequency specified. Moreover, the vibration analysis procedure demonstrates that amplitudes can be estimated in submillimetre range accuracy, frequencies with an accuracy better than 0.1 Hz and damping ratio coefficients with an accuracy better than 0.1 and 0.2 % for modal and system damping, respectively.

Sinai and Exodus: Two Grounds for Hope in the Jewish Tradition

1978 ◽  
Vol 14 (3) ◽  
pp. 373-387
Author(s):  
David Hartman
Keyword(s):  
Jewish Tradition ◽  
Look Ahead ◽  
The World ◽  
The Future ◽  
Sole Criterion ◽  
The Given ◽  
Better Than

Hope is a category of transcedence, by means of which a man does not permit what he senses and experiences to be the sole criterion of what is possible. It is the belief or the conviction that present reality (what I see) does not exhaust the potentialities of the given data. Hope opens the present to the future; it enables a man to look ahead, to break the fixity of what he observes, and to perceive the world as open-textured. The categories of possibility and of transcendence interweave a closely stitched fabric - hope says that tomorrow can be better than today.

scholarly journals Context-Aware Adaptation of Component-Based Systems: An Active Repository Approach

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Sindolfo Miranda Filho ◽  
Julio Melo ◽  
Luiz Eduardo Leite ◽  
Guido Lemos
Keyword(s):  
Context Aware ◽  
Current Configuration ◽  
Fuzzy Logic Algorithm ◽  
Running System ◽  
Component Based Software Engineering ◽  
Context Aware System ◽  
The Given ◽  
To Receive ◽  
Component Repository

Context-aware systems are able to monitor and automatically adapt their operation accordingly to the execution context in which they are introduced. Component-based software engineering (CBSE) focuses on the development and reuse of self-contained software assets in order to achieve better productivity and quality. In order to store and retrieve components, CBSE employs component repository systems to provide components to the system developers. This paper presents an active component repository that is able to receive the current configuration from the context-aware system and compute the components and the new architecture that better fit the given context. Since the repository has a wide knowledge of available components, it can better decide which configuration is more suitable to the running system. The repository applies Fuzzy logic algorithm to evaluate the adequacy level of the components and GRASP algorithm to mount the new system architecture. In order to verify the feasibility of our approach, we use a digital TV middleware case study to achieve experimental results.

State Of Purine Exchange And Microalbuminuria In Patients With Metabolic Syndrome

2021 ◽  
Vol 03 (01) ◽  
pp. 46-54
Author(s):  
Irodakhon Makhkambaevna Tashtemirova ◽  
Keyword(s):  
Metabolic Syndrome ◽  
Arterial Hypertension ◽  
Functional Condition ◽  
Adrenal System ◽  
The Given ◽  
Healthy Persons

The aim of the given work was study interactions of impairments sympa-thetic – adrenal systems functional condition and processes of peroxidal oxida-tion of lipids in woman with metabolic syndrome. 107women at the age of 25-49 were observation. They were randomized into 3 groups: I (control) – 15 healthy persons, II – 43 patients with arterial hypertension, III – 49 women with arterial hypertension in combination with metabolic syndrome. The results of carried investigations showed that activation of sympathetic adrenal system and processes of peroxidal oxidation of lipids took place in metabolic syn-drome. Marked lowering of sympathetic – adrenal system key ferment catechol-amins (MAO monoaminooxidaze) desamidization activity and considerable ac-tivation of peroxidal oxidation of lipid products which have great significance in revealing the mechanism of metabolic syndrome development were observed in metabolic syndrome. This results in the prolonged toxic influence of catechola-mins on myocardium.

Vibration Dissipation Characteristics of Symmetrical Piezoelectric Networks With Passive Branches

2012 ◽  
Author(s):  
Yu Fan ◽  
Lin Li
Keyword(s):  
Dynamic Models ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Design Guidelines ◽  
Connection Form ◽  
Network Connection ◽  
Lumped Parameter ◽  
The Given ◽  
Parameter Approach ◽  
Better Than

In this paper, a new vibration reduction approach by means of symmetric piezoelectric network is proposed, combining energy harvesting and vibration reduction. The system could be constructed by several individual structures with identical mechanical parameters, such as blades of rotor machinery. Two basic forms of network-connection are studied, in which dissipation of both mechanical and electric field is considered. Dynamic models are established by the Lumped Parameter approach and Kirchhoff’s Circuit Theorem, and the normalizing process is used to make the models more general. Subsequently, the modal information and harmonic response of piezoelectric networks with an arbitrary number of components are obtained. Based on the dynamic characteristics of piezoelectric networks, the mechanism of vibration-suppression behavior of such systems is studied. Design guidelines of these vibration reduction systems are established via parameter studies. Eventually, the optimized parameters of each network-connection form are obtained analytically. It is shown that the symmetric piezoelectric network can suppress the response of the given frequency to zero, and also perform better than pure passive piezoelectric shunts in resonant frequency band.

Jung's Contribution to Clinical Psychiatry

1935 ◽  
Vol 28 (8) ◽  
pp. 1051-1064
Author(s):  
Murdo Mackenzie
Keyword(s):  
Clinical Psychiatry ◽  
Clinical Medicine ◽  
Psychological Adaptation ◽  
Adequate Description ◽  
Unique Method ◽  
Basic Functions ◽  
Possible Cause ◽  
Better Than

This attempt to correlate Jung's work with practical psychiatry is concerned mainly with his conception of clinical types. Jung went far away from the provinces of clinical medicine and psychiatry for his evidence, and the possible cause for this is discussed. He expands his view of introversion and extraversion, and so the suggestion is made that for practical purposes his early limitation of these terms should be maintained. The difficulties encountered in type description by comparison and contrast are emphasized. The value of his conception of basic functions is discussed and criticized. A review is made of the personalities he describes, and a simplification of his resulting classification suggested for practical purposes. The notion is put forward that Jung describes one type in psychological adaptation much better than any others, and it is hinted that his psycho-pathological description of this type in nerve disorder constitutes his main contribution to clinical psychiatry. A review of the treatable nerve disorders suggests that this disorder has received more adequate description from Jung than any other, and reveals a unique method of investigation and therapy. This does not apply to his other descriptions. Possibly some of the vagueness attributed to Jung is because he did not give this disorder an adequate diagnosis, and an explanation for this is offered. The correlation between the simplified classification and the classification of treatable nerve disorders is close, and it is suggested that this constitutes Jung's contribution to clinical psychiatry in general. The application of Jung's principles is of daily help to the practising psychiatrist.

scholarly journals Developing a Novel Miniature 3D-Printed TLBS with High Mechanical Efficiency and Better Controllability

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 662
Author(s):  
Chung-Wei Lee ◽  
Jung-Hua Chou
Keyword(s):  
Mechanical Efficiency ◽  
Ball Screw ◽  
Maximum Efficiency ◽  
Design Parameters ◽  
Affecting Factors ◽  
Lead Screw ◽  
Torque Loss ◽  
3D Printed ◽  
Novel Model ◽  
Better Than

This paper focuses on the development of a 3D-printed threadless ball screw (TLBS) for the applications that require miniaturization, customization, and accuracy controllability. To enhance the efficiency of the TLBS, a novel model of the TLBS for analyzing the mechanical efficiency is presented to obtain the key affecting factors. From these factors, the design parameters for fabrication are determined. For miniaturization, a novel 3D-printed one-piece preloaded structure of light weight of 0.9 g is implemented as the TLBS nut part. Experimental results show that the measured mechanical efficiency of TLBS is close to that predicted by the theoretical model with a normalized root mean square error of 3.16%. In addition, the mechanical efficiency of the present TLBS (maximum efficiency close to 90%) is better than that of the lead screw and close to the ball screw. The unique characteristic of the present TLBS is that its total torque loss is a weak function of the load, a phenomenon not observed in either the ball screw or the lead screw. This characteristic is advantageous in enhancing the controllability of accuracy at different loads.

scholarly journals Localization of Autonomous Robot in an Urban Area Based on SURF Feature Extraction of Images

2020 ◽  
Vol 11 (4) ◽  
pp. 84-111
Author(s):  
Abu Sadat Mohammed Yasin ◽  
Md. Majharul Haque ◽  
Md. Nasim Adnan ◽  
Sonia Rahnuma ◽  
Anowar Hossain ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Image Matching ◽  
Autonomous Robots ◽  
Network Connectivity ◽  
Specific Area ◽  
Autonomous Robot ◽  
Elapsed Time ◽  
Global Positioning ◽  
The Given ◽  
Better Than

An autonomous robot is now an internationally discussed topic to ease the life of humans. Localization and movement are two rudimentary necessities of the autonomous robots before accomplishing any job. So, many researchers have proposed methods of localization using external tools like network connectivity, global positioning system (GPS), etc. However, if these tools are lost, either the movement will be paused, or the robot will be derailed from the actual mission. In these circumstances, the authors propose an approach to localize an autonomous robot in a specific area using the given set of images without external help. The image database has been prepared and kept in the internal memory of robot so that image matching can be done quickly. The localization method has been accomplished using three algorithms: (1) SURF, (2) ICP-BP, and (3) EMD. In the evaluation, SURF has been found better than ICP-BP and EMD in terms of accuracy and elapsed time. The authors believe that the proposed method will add value to other methods using some external tools even when those tools are unavailable.

scholarly journals The Effect of Exit Strategy on Optimal Portfolio Selection with Birandom Returns

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Guohua Cao ◽  
Dan Shan
Keyword(s):  
Portfolio Selection ◽  
Stock Return ◽  
Optimal Portfolio ◽  
Exit Strategy ◽  
Hybrid Intelligent Algorithm ◽  
Optimal Portfolio Selection ◽  
Stop Loss ◽  
The Given ◽  
Safety First ◽  
Better Than

The aims of this paper are to use a birandom variable to denote the stock return selected by some recurring technical patterns and to study the effect of exit strategy on optimal portfolio selection with birandom returns. Firstly, we propose a new method to estimate the stock return and use birandom distribution to denote the final stock return which can reflect the features of technical patterns and investors' heterogeneity simultaneously; secondly, we build a birandom safety-first model and design a hybrid intelligent algorithm to help investors make decisions; finally, we innovatively study the effect of exit strategy on the given birandom safety-first model. The results indicate that (1) the exit strategy affects the proportion of portfolio, (2) the performance of taking the exit strategy is better than when the exit strategy is not taken, if the stop-loss point and the stop-profit point are appropriately set, and (3) the investor using the exit strategy become conservative.

Tracing exploratory modes in digital collections of museum Web sites using reverse information architecture

First Monday ◽  
2017 ◽  
Vol 22 (4) ◽  
Author(s):  
Sarah Kreiseler ◽  
Viktoria Brüggemann ◽  
Marian Dörk
Keyword(s):  
Web Sites ◽  
Information Architecture ◽  
Data Sets ◽  
Digital Collections ◽  
Interface Elements ◽  
Web Interfaces ◽  
Making Sense ◽  
Unique Method ◽  
The Given ◽  
The Web

Museums are broadening their program beyond the physical institutions by providing digital collections online. In digital collections, objects are prepared and presented particularly for the Web and the ambition is to provide the entirety of a physical collection. To make these rich and comprehensive data sets accessible, an explore mode is increasingly offered. The present study considers this mode, first by making sense of the term “exploration” and suggesting four functional principles in support of exploration in digital collections — view, movement, contextualization, and participation. On this basis, we compare eight well-known museums with regard to the explore modes for their digital collections. We have devised a three-part methodology, reverse information architecture, to address the question: How is the function of exploration manifested in the structure and interface elements of digital collections? With this unique method we use the given content to investigate how far the four principles are implemented in explore modes of digital collections and, broadly said, how explorable they are. The introduced approach to studying digital collections could be opened up to other fields to analyze a variety of Web interfaces in general.

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