scholarly journals Vibrodiagnostics Used for Evaluating the Technical Condition of a Mechanical Gearbox

2018 ◽  
Vol 198 ◽  
pp. 02002
Author(s):  
Jan Furch ◽  
Jiří Stodola ◽  
Josef Glos
Keyword(s):  
Life Cycle ◽  
Root Mean Square ◽  
Technical Condition ◽  
The Other ◽  
Technical Diagnostics ◽  
Mean Square ◽  
Crest Factor ◽  
Road Vehicle ◽  
Vibration Signals ◽  
Fourth Position

The aim of this article is to evaluate the technical condition of a mechanical four-speed gearbox tightly connected to a mechanical two-speed auxiliary gearbox placed in an off-road vehicle. When observing the technical condition of the mechanical gearbox, we used one of technical diagnostics methods, namely vibrodiagnostics. The mechanical gearbox was monitored during all its life cycle up to failure occurrence. In the article there is a detailed description of the stand where the gearbox technical condition was monitored. When observing vibration signals, we used four tri-axial sensors placed in four selected spots depending on the design arrangement of antifriction bearings. In order to evaluate the measured results, two methods were applied, namely the root mean square gRMS based on the measured acceleration in three axes. The other method used for monitoring the technical condition was the Crest factor. The aim of the experiment was to monitor the technical condition of the mechanical gearbox, mainly its antifriction bearings, therefore the values were measured when the gear was put into fourth position and into overdrive in the auxiliary gearbox. When the gear is put into fourth position, the torque is transmitted from the motor through the main gearbox and the auxiliary gearbox directly. Single gearbox wheels are engaged but not loaded (they do not transmit the torque). At the end of our article we introduced the measured values along with the oral evaluation of the technical condition of the mechanical gearbox and the auxiliary gearbox.

scholarly journals Equation Based New Methods for Residential Load Forecasting

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6378
Author(s):  
S. M. Mahfuz Alam ◽  
Mohd. Hasan Ali
Keyword(s):  
Root Mean Square ◽  
Load Forecasting ◽  
Residential Building ◽  
The Other ◽  
Support Vector ◽  
Linear Regression Method ◽  
Mean Square ◽  
Performance Indices ◽  
Degree Days ◽  
Average Percentage

This work proposes two non-linear and one linear equation-based system for residential load forecasting considering heating degree days, cooling degree days, occupancy, and day type, which are applicable to any residential building with small sets of smart meter data. The coefficients of the proposed nonlinear and linear equations are tuned by particle swarm optimization (PSO) and the multiple linear regression method, respectively. For the purpose of comparison, a subtractive clustering based adaptive neuro fuzzy inference system (ANFIS), random forests, gradient boosting trees, and long-term short memory neural network, conventional and modified support vector regression methods were considered. Simulations have been performed in MATLAB environment, and all the methods were tested with randomly chosen 30 days data of a residential building in Memphis City for energy consumption prediction. The absolute average error, root mean square error, and mean average percentage errors are tabulated and considered as performance indices. The efficacy of the proposed systems for residential load forecasting over the other systems have been validated by both simulation results and performance indices, which indicate that the proposed equation-based systems have the lowest absolute average errors, root mean square errors, and mean average percentage errors compared to the other methods. In addition, the proposed systems can be easily practically implemented.

Evaluation of High-Resolution Precipitation Products over Southwest China

2020 ◽  
Vol 21 (11) ◽  
pp. 2691-2712
Author(s):  
Yanbo Nie ◽  
Jianqi Sun
Keyword(s):  
High Resolution ◽  
Root Mean Square ◽  
Extreme Precipitation ◽  
Southwest China ◽  
Daily Precipitation ◽  
The Other ◽  
Future Research ◽  
Monthly Precipitation ◽  
Mean Square ◽  
Mean Square Errors

AbstractThe evaluation of gridded high-resolution precipitation products (HRPPs) is important in areas with complex topography, because rain gauges that are unevenly and sparsely distributed over an area cannot effectively reflect the spatial variabilities of the precipitation and related extremes in detail. In this study, the applicability of six satellite-based precipitation products (TMPA 3B42V7, IMERG, GSMaP-Gauge, CMORPH-CRT, PERSIANN-CDR, and GPCP) and five gauge-based precipitation products (APHRODITE, CN05.1, GPCC-D, GPCC-M, and CRU) over southwest China from 1998 to 2016 is evaluated by performing a comparison with meteorological station observations. The results show that GPCC-M exhibits the best performances for annual, seasonal, and monthly precipitation, which is supported by the lowest root-mean-square errors (RMSEs) for annual and seasonal precipitation and the lowest normalized root-mean-square error (NRMSE) for monthly precipitation. According to the NRMSE and critical success index (CSI), CN05.1 outperforms the other HRPPs at detecting daily precipitation; however, CN05.1 tends to overestimate the frequencies of light precipitation and underestimate the frequencies of heavy precipitation, which is reflected by the probability density function (PDF) for daily precipitation. The bias ratio (BIAS) and extreme precipitation indices show that IMERG shows numerous advantages over the other HRPPs in detecting extreme precipitation and estimating the precipitation intensity. Such results are helpful for future research on precipitation/extremes and related hydrometeorological disasters that occur throughout southwest China.

Analysis of the wagons-tanks technical condition of the chemical industry park

2019 ◽  
Vol 24 (3-4) ◽  
pp. 82-92
Author(s):  
Voropai V. ◽  
◽  
Chebanov V. ◽  
Keyword(s):  
Life Cycle ◽  
Chemical Industry ◽  
Statistical Data ◽  
Technical Condition ◽  
Technical Diagnostics ◽  
Information Set

The article brings statistical data on the technical condition of the wagons-tanks of one of the largest enterprises of the Ukrainian chemical industry. The technique of monitoring the technical condition is explained, the classification of damage to wagons-tanks depending on the stages of the life cycle is proposed, the distribution of damage depending on the stages of the life cycle is shown. The information set forth in the article provides the basis for conducting technical diagnostics in order to justify the further term of maintenance

scholarly journals STATEMENT OF THE PROBLEM FOR TECHNICAL DIAGNOSTIC TANK CARS

2021 ◽  
pp. 68
Author(s):  
V. VOROPAI
Keyword(s):  
Life Cycle ◽  
Technical Condition ◽  
Industrial Enterprise ◽  
Practical Significance ◽  
Rolling Stock ◽  
Alternative Form ◽  
Technical Diagnostics ◽  
Main Task ◽  
Global Management ◽  
Modern Technologies

The purpose of the work is to formulate the problem of technical diagnostics of tank cars. Research methods. Methods of formal logic were used methods of the theory of reliability and probability were used to describe the stages of solving the problem. Results. A study of a large array of data on the performance indicators of tank cars for the transportation of liquefied gases of the fleet of a chemical industry enterprise in Ukraine was carried out. The results of technical inspection of tank cars were obtained. A hypothesis has been formed about the possibility of increasing the resource of tank cars of an industrial park for their further operation. A proposal was put forward to consider the last stage of the life cycle as the stage "Life cycle renewal and recycling", which is not defined in Statement Standart. It should in an alternative form represent the stages of "utilization", "modernization", "modification" and "recycling", this will correspond to modern technologies on the scale of the global management of any resources. The research task was formulated, which determines the main task - the possibility of increasing the resource of tank cars of the operating fleet of an industrial enterprise using the methods of technical diagnostics. Practical significance. The solution to the task of determining the technical condition of tank cars will allow an industrial enterprise to reasonably operate the rolling stock during the forecast period.

scholarly journals A Modified Evaluation Approach for Direct Assessment of Program Outcomes: Medical Equipment Technology Program as Case Study

2020 ◽  
Vol 15 (04) ◽  
pp. 22
Author(s):  
Mohamed Ibrahim Waly
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Suggested Method ◽  
The Other ◽  
Second Step ◽  
Mean Square ◽  
Program Outcomes ◽  
Direct Assessment ◽  
General Capacity

Abstract Academic accreditation criteria require a powerful method to evaluate program outcomes (POs). The most recent studies recommend the use of both direct and indirect assessments to evaluate the actual achievements of POs. This study aimed to provide an easily implemented method based on direct assessment and other integrated variables that reflect the reality of students' achievement of POs. The suggested method, based on weight average equation, was presented and compared with the other two methods. The comparative study was designed on the basis of two steps. First, the results of each method were compared with the result of the general capacity exam, using root mean square error (27 students, male, from level four with 6 courses). The second step was based on statistical analysis (paired t-test) of results from the methods for the same batch of students (from level 3 to level 6, with 22 courses). In the first step, the suggested method resulted in the lowest root mean square error relative to the general capacity exam (9%). In the second step there was a significant difference between the mean of the suggested method and other methods (69.8040 ± 6.59, P-value < 0.05). The evaluation procedure for POs is an integral component of the education process. Various variables are integrated to reflect the actual achievement of students. The suggested method reflected the reality of PO achievements more accurately than the other methods, which proved sensitivity to the number of course learning outcomes (CLOs).

scholarly journals Validation metrics of homogenization techniques on artificially inhomogenized monthly temperature networks in Sweden and Slovenia (1950–2005)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Roberto Coscarelli ◽  
Giulio Nils Caroletti ◽  
Magnus Joelsson ◽  
Erik Engström ◽  
Tommaso Caloiero
Keyword(s):  
Missing Data ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Absolute Error ◽  
The Other ◽  
Mean Square ◽  
Validation Metrics ◽  
Absolute Bias ◽  
Climate Signals

AbstractIn order to correctly detect climate signals and discard possible instrumentation errors, establishing coherent data records has become increasingly relevant. However, since real measurements can be inhomogeneous, their use for assessing homogenization techniques is not directly possible, and the study of their performance must be done on homogeneous datasets subjected to controlled, artificial inhomogeneities. In this paper, considering two European temperature networks over the 1950–2005 period, up to 7 artificial breaks and an average of 107 missing data per station were introduced, in order to determine that mean square error, absolute bias and factor of exceedance can be meaningfully used to validate the best-performing homogenization technique. Three techniques were used, ACMANT and two versions of HOMER: the standard, automated setup mode and a manual setup. Results showed that the HOMER techniques performed better regarding the factor of exceedance, while ACMANT was best with regard to absolute error and root mean square error. Regardless of the technique used, it was also established that homogenization quality anti-correlated meaningfully to the number of breaks. On the other hand, as missing data are almost always replaced in the two HOMER techniques, only ACMANT performance is significantly, negatively affected by the amount of missing data.

dSPACE implementation for a proportional–integral-based root mean square voltage controller used in stand-alone wind energy conversion systems

2018 ◽  
Vol 43 (4) ◽  
pp. 404-419 ◽  
Author(s):  
Rachid El Akhrif ◽  
Ahmed Abbou ◽  
Chaymae Laoufi ◽  
Mohamed Ferfra
Keyword(s):  
Permanent Magnet ◽  
Root Mean Square ◽  
Pulse Width Modulation ◽  
Induction Machine ◽  
Synchronous Generator ◽  
The Other ◽  
Induction Generator ◽  
Mean Square ◽  
Permanent Magnet Synchronous Generator ◽  
Energy Conversion Systems

The induction machine and the synchronous machine are very promising in renewable energy production for uses in wind turbines to produce energy in remote areas, and we note that self-excited induction generator is more adapted due to difficult geographical conditions and best cost; on the other hand, permanent magnet synchronous generator works without any excitation system; all of these have a major problem in use which is the stability of voltage. To solve this problem, we propose in this article the examination of a control plot for keeping the produced root mean square voltage steady. This article presents an experimental comparative study of performances in terms of root mean square voltage on two possible small wind turbine systems. One of the systems is based on permanent magnet synchronous generator and the other is based on self-excited induction generator. Taking into account the parameters of load and wind speed, experimental test benches for both systems are implemented using the dSPACE card for controlling the pulse width modulation inverter to impose the Vrms value of the desired output voltage.

Efficiency of application of the phase-chronometric method and neurodiagnostics for monitoring the degradation of rolling bearings during operation

2020 ◽  
pp. 43-50
Author(s):  
A.S. Komshin ◽  
K.G. Potapov ◽  
V.I. Pronyakin ◽  
A.B. Syritskii
Keyword(s):  
Life Cycle ◽  
Wavelet Analysis ◽  
Metrological Support ◽  
Rolling Bearing ◽  
Technical Condition ◽  
Measurement Information ◽  
Rolling Bearings ◽  
Vibration Diagnostics ◽  
Bearing Life ◽  
Alternative Approach

The paper presents an alternative approach to metrological support and assessment of the technical condition of rolling bearings in operation. The analysis of existing approaches, including methods of vibration diagnostics, envelope analysis, wavelet analysis, etc. Considers the possibility of applying a phase-chronometric method for support on the basis of neurodiagnostics bearing life cycle on the basis of the unified format of measurement information. The possibility of diagnosing a rolling bearing when analyzing measurement information from the shaft and separator was evaluated.

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